diff --git a/.travis.yml b/.travis.yml
deleted file mode 100644
index ca4e7a47..00000000
--- a/.travis.yml
+++ /dev/null
@@ -1,423 +0,0 @@
-matrix:
-  allow_failures:
-    - language: nix
-  fast_finish: true
-  include:
-    - env: DISPLAY=true   USE_STACK_YAML="stack-8.0.yaml"     # GHC 8.0.2
-      language: python
-      dist: xenial
-      # Test against different stack LTS versions.
-
-      # Choose a lightweight base image; we provide our own build tools.
-      python: "3.6"
-
-      # Enable caching.
-      sudo: false
-
-      # Caching so the next build will be fast too.
-      # These caches are the same between resolvers, but this is fine, 
-      # as Stack differentiates between its resolvers.
-      cache:
-        directories:
-        - $HOME/.ghc
-        - $HOME/.cabal
-        - $HOME/.stack
-
-      # Enable packages we need.
-      # Not all packages are available – see before_install for from-source builds. 
-      addons:
-        apt:
-          packages:
-            - libmagic-dev     # magic
-            - libgmp-dev       # ghc
-            - libblas-dev      # hmatrix
-            - liblapack-dev    # hmatrix
-            - libcairo2-dev    # cairo
-            - libpango1.0-dev  # pango
-            - libzmq3-dev      # zmq
-
-      before_install:
-          # Download and unpack the stack executable
-        - export PATH=$HOME/.local/bin:$PATH
-        - mkdir -p ~/.local/bin
-        - curl -L https://get.haskellstack.org/stable/linux-x86_64.tar.gz | tar xz --wildcards --strip-components=1 -C ~/.local/bin '*/stack'
-
-          # Upgrades to avoid later build problems
-        - pip install -U pip
-        - pip install -U setuptools
-
-          # Install from requirements.txt
-        - pip install -r requirements.txt
-
-      # This step takes the longest, and is what generates the Stack cache. 
-      install:
-        - |
-          # Used to avoid 'source and destination file are the same' error
-          mv $USE_STACK_YAML intermediate-stack.yaml
-          mv intermediate-stack.yaml stack.yaml
-
-          echo "apply-ghc-options: everything" >> stack.yaml
-
-        - stack setup
-        - stack install gtk2hs-buildtools
-        - stack build hmatrix
-        - stack build --dependencies-only
-
-      script:
-        # Ensure that ipython-kernel examples build successfully.
-        - stack build ipython-kernel --flag ipython-kernel:examples
-        - stack test --no-terminal
-        - |
-          set -e
-          if $DISPLAY; then
-              TOP=$(pwd)
-              stack build --no-terminal
-
-              # Ensure that IHaskell notebook remains unchanged.
-              # Run the notebook to regenerate the outputs, then compare the new notebook to the old one.
-              stack install
-              stack exec -- ihaskell install --stack
-              test/acceptance.nbconvert.sh stack exec -- jupyter nbconvert
-          fi
-    - env: DISPLAY=true   USE_STACK_YAML="stack-8.2.yaml"     # GHC 8.2.2
-      language: python
-      dist: xenial
-      # Test against different stack LTS versions.
-
-      # Choose a lightweight base image; we provide our own build tools.
-      python: "3.6"
-
-      # Enable caching.
-      sudo: false
-
-      # Caching so the next build will be fast too.
-      # These caches are the same between resolvers, but this is fine, 
-      # as Stack differentiates between its resolvers.
-      cache:
-        directories:
-        - $HOME/.ghc
-        - $HOME/.cabal
-        - $HOME/.stack
-
-      # Enable packages we need.
-      # Not all packages are available – see before_install for from-source builds. 
-      addons:
-        apt:
-          packages:
-            - libmagic-dev     # magic
-            - libgmp-dev       # ghc
-            - libblas-dev      # hmatrix
-            - liblapack-dev    # hmatrix
-            - libcairo2-dev    # cairo
-            - libpango1.0-dev  # pango
-            - libzmq3-dev      # zmq
-
-      before_install:
-          # Download and unpack the stack executable
-        - export PATH=$HOME/.local/bin:$PATH
-        - mkdir -p ~/.local/bin
-        - curl -L https://get.haskellstack.org/stable/linux-x86_64.tar.gz | tar xz --wildcards --strip-components=1 -C ~/.local/bin '*/stack'
-
-          # Upgrades to avoid later build problems
-        - pip install -U pip
-        - pip install -U setuptools
-
-          # Install from requirements.txt
-        - pip install -r requirements.txt
-
-      # This step takes the longest, and is what generates the Stack cache. 
-      install:
-        - |
-          # Used to avoid 'source and destination file are the same' error
-          mv $USE_STACK_YAML intermediate-stack.yaml
-          mv intermediate-stack.yaml stack.yaml
-
-          echo "apply-ghc-options: everything" >> stack.yaml
-
-        - stack setup
-        - stack install gtk2hs-buildtools
-        - stack build hmatrix
-        - stack build --dependencies-only
-
-      script:
-        # Ensure that ipython-kernel examples build successfully.
-        - stack build ipython-kernel --flag ipython-kernel:examples
-        - stack test --no-terminal
-        - |
-          set -e
-          if $DISPLAY; then
-              TOP=$(pwd)
-              stack build --no-terminal
-
-              # Ensure that IHaskell notebook remains unchanged.
-              # Run the notebook to regenerate the outputs, then compare the new notebook to the old one.
-              stack install
-              stack exec -- ihaskell install --stack
-              test/acceptance.nbconvert.sh stack exec -- jupyter nbconvert
-          fi
-    - env: DISPLAY=true   USE_STACK_YAML="stack-8.4.yaml"     # GHC 8.4.3
-      language: python
-      dist: xenial
-      # Test against different stack LTS versions.
-
-      # Choose a lightweight base image; we provide our own build tools.
-      python: "3.6"
-
-      # Enable caching.
-      sudo: false
-
-      # Caching so the next build will be fast too.
-      # These caches are the same between resolvers, but this is fine, 
-      # as Stack differentiates between its resolvers.
-      cache:
-        directories:
-        - $HOME/.ghc
-        - $HOME/.cabal
-        - $HOME/.stack
-
-      # Enable packages we need.
-      # Not all packages are available – see before_install for from-source builds. 
-      addons:
-        apt:
-          packages:
-            - libmagic-dev     # magic
-            - libgmp-dev       # ghc
-            - libblas-dev      # hmatrix
-            - liblapack-dev    # hmatrix
-            - libcairo2-dev    # cairo
-            - libpango1.0-dev  # pango
-            - libzmq3-dev      # zmq
-
-      before_install:
-          # Download and unpack the stack executable
-        - export PATH=$HOME/.local/bin:$PATH
-        - mkdir -p ~/.local/bin
-        - curl -L https://get.haskellstack.org/stable/linux-x86_64.tar.gz | tar xz --wildcards --strip-components=1 -C ~/.local/bin '*/stack'
-
-          # Upgrades to avoid later build problems
-        - pip install -U pip
-        - pip install -U setuptools
-
-          # Install from requirements.txt
-        - pip install -r requirements.txt
-
-      # This step takes the longest, and is what generates the Stack cache. 
-      install:
-        - |
-          # Used to avoid 'source and destination file are the same' error
-          mv $USE_STACK_YAML intermediate-stack.yaml
-          mv intermediate-stack.yaml stack.yaml
-
-          echo "apply-ghc-options: everything" >> stack.yaml
-
-        - stack setup
-        # - stack install gtk2hs-buildtools
-        - stack build hmatrix
-        - stack build --dependencies-only
-
-      script:
-        # Ensure that ipython-kernel examples build successfully.
-        - stack build ipython-kernel --flag ipython-kernel:examples
-        - stack test --no-terminal
-        - |
-          set -e
-          if $DISPLAY; then
-              TOP=$(pwd)
-              stack build --no-terminal
-
-              # Ensure that IHaskell notebook remains unchanged.
-              # Run the notebook to regenerate the outputs, then compare the new notebook to the old one.
-              stack install
-              stack exec -- ihaskell install --stack
-              test/acceptance.nbconvert.sh stack exec -- jupyter nbconvert
-          fi
-    - env: DISPLAY=true   USE_STACK_YAML="stack.yaml"     # GHC 8.6.5
-      language: python
-      dist: xenial
-      # Test against different stack LTS versions.
-
-      # Choose a lightweight base image; we provide our own build tools.
-      python: "3.6"
-
-      # Enable caching.
-      sudo: false
-
-      # Caching so the next build will be fast too.
-      # These caches are the same between resolvers, but this is fine, 
-      # as Stack differentiates between its resolvers.
-      cache:
-        directories:
-        - $HOME/.ghc
-        - $HOME/.cabal
-        - $HOME/.stack
-
-      # Enable packages we need.
-      # Not all packages are available – see before_install for from-source builds. 
-      addons:
-        apt:
-          packages:
-            - libmagic-dev     # magic
-            - libgmp-dev       # ghc
-            - libblas-dev      # hmatrix
-            - liblapack-dev    # hmatrix
-            - libcairo2-dev    # cairo
-            - libpango1.0-dev  # pango
-            - libzmq3-dev      # zmq
-
-      before_install:
-          # Download and unpack the stack executable
-        - export PATH=$HOME/.local/bin:$PATH
-        - mkdir -p ~/.local/bin
-        - curl -L https://get.haskellstack.org/stable/linux-x86_64.tar.gz | tar xz --wildcards --strip-components=1 -C ~/.local/bin '*/stack'
-
-          # Upgrades to avoid later build problems
-        - pip install -U pip
-        - pip install -U setuptools
-
-          # Install from requirements.txt
-        - pip install -r requirements.txt
-
-      # This step takes the longest, and is what generates the Stack cache. 
-      install:
-        - |
-          # Used to avoid 'source and destination file are the same' error
-          mv $USE_STACK_YAML intermediate-stack.yaml
-          mv intermediate-stack.yaml stack.yaml
-
-          echo "apply-ghc-options: everything" >> stack.yaml
-
-        - stack setup
-        # - stack install gtk2hs-buildtools
-        - stack build hmatrix
-        - stack build --dependencies-only
-
-      script:
-        # Ensure that ipython-kernel examples build successfully.
-        - stack build ipython-kernel --flag ipython-kernel:examples
-        - stack test --no-terminal
-        - |
-          set -e
-          if $DISPLAY; then
-              TOP=$(pwd)
-              stack build --no-terminal
-
-              # Ensure that IHaskell notebook remains unchanged.
-              # Run the notebook to regenerate the outputs, then compare the new notebook to the old one.
-              stack install
-              stack exec -- ihaskell install --stack
-              test/acceptance.nbconvert.sh stack exec -- jupyter nbconvert
-          fi
-    - env: DISPLAY=true   USE_STACK_YAML="stack-8.8.yaml"     # GHC 8.8.1
-      language: python
-      dist: xenial
-      # Test against different stack LTS versions.
-
-      # Choose a lightweight base image; we provide our own build tools.
-      python: "3.6"
-
-      # Enable caching.
-      sudo: false
-
-      # Caching so the next build will be fast too.
-      # These caches are the same between resolvers, but this is fine, 
-      # as Stack differentiates between its resolvers.
-      cache:
-        directories:
-        - $HOME/.ghc
-        - $HOME/.cabal
-        - $HOME/.stack
-
-      # Enable packages we need.
-      # Not all packages are available – see before_install for from-source builds. 
-      addons:
-        apt:
-          packages:
-            - libmagic-dev     # magic
-            - libgmp-dev       # ghc
-            - libblas-dev      # hmatrix
-            - liblapack-dev    # hmatrix
-            - libcairo2-dev    # cairo
-            - libpango1.0-dev  # pango
-            - libzmq3-dev      # zmq
-
-      before_install:
-          # Download and unpack the stack executable
-        - export PATH=$HOME/.local/bin:$PATH
-        - mkdir -p ~/.local/bin
-        - curl -L https://get.haskellstack.org/stable/linux-x86_64.tar.gz | tar xz --wildcards --strip-components=1 -C ~/.local/bin '*/stack'
-
-          # Upgrades to avoid later build problems
-        - pip install -U pip
-        - pip install -U setuptools
-
-          # Install from requirements.txt
-        - pip install -r requirements.txt
-
-      # This step takes the longest, and is what generates the Stack cache. 
-      install:
-        - |
-          # Used to avoid 'source and destination file are the same' error
-          mv $USE_STACK_YAML intermediate-stack.yaml
-          mv intermediate-stack.yaml stack.yaml
-
-          echo "apply-ghc-options: everything" >> stack.yaml
-
-        - stack setup
-        # - stack install gtk2hs-buildtools
-        - stack build hmatrix
-        - stack build --dependencies-only
-
-      script:
-        # Ensure that ipython-kernel examples build successfully.
-        - stack build ipython-kernel --flag ipython-kernel:examples
-        - stack test --no-terminal
-        - |
-          set -e
-          if $DISPLAY; then
-              TOP=$(pwd)
-              stack build --no-terminal
-
-              # Ensure that IHaskell notebook remains unchanged.
-              # Run the notebook to regenerate the outputs, then compare the new notebook to the old one.
-              stack install
-              stack exec -- ihaskell install --stack
-              test/acceptance.nbconvert.sh stack exec -- jupyter nbconvert
-          fi
-    - language: nix
-      nix: 2.3
-      dist: xenial
-      env: NIXPKGS_ALLOW_BROKEN=1
-      before_install:
-        - export NIX_CONF_DIR=~
-        - echo "binary-caches = https://cache.nixos.org https://ihaskell.cachix.org" >> $NIX_CONF_DIR/nix.conf
-        - echo "binary-cache-public-keys = cache.nixos.org-1:6NCHdD59X431o0gWypbMrAURkbJ16ZPMQFGspcDShjY= ihaskell.cachix.org-1:WoIvex/Ft/++sjYW3ntqPUL3jDGXIKDpX60pC8d5VLM=" >> $NIX_CONF_DIR/nix.conf
-        - glibcLocales=$(nix-build https://github.com/NixOS/nixpkgs-channels/tarball/nixos-20.03 -A glibcLocales)
-        - echo $glibcLocales
-        - export LOCALE_ARCHIVE_2_27="${glibcLocales}/lib/locale/locale-archive"
-      script:
-        - nix-shell -I nixpkgs=https://github.com/NixOS/nixpkgs-channels/tarball/nixos-20.03 -p cachix --run 'cachix push ihaskell --watch-store &'
-        - >
-          nix-build
-          -I nixpkgs=https://github.com/NixOS/nixpkgs-channels/tarball/nixos-20.03
-          release.nix
-          --argstr compiler "ghc865"
-        - test/acceptance.nbconvert.sh result/bin/ihaskell-nbconvert
-    - language: nix
-      nix: 2.3
-      dist: xenial
-      env: NIXPKGS_ALLOW_BROKEN=1
-      before_install:
-        - export NIX_CONF_DIR=~
-        - echo "binary-caches = https://cache.nixos.org https://ihaskell.cachix.org" >> $NIX_CONF_DIR/nix.conf
-        - echo "binary-cache-public-keys = cache.nixos.org-1:6NCHdD59X431o0gWypbMrAURkbJ16ZPMQFGspcDShjY= ihaskell.cachix.org-1:WoIvex/Ft/++sjYW3ntqPUL3jDGXIKDpX60pC8d5VLM=" >> $NIX_CONF_DIR/nix.conf
-        - glibcLocales=$(nix-build https://github.com/NixOS/nixpkgs-channels/tarball/nixos-20.03 -A glibcLocales)
-        - echo $glibcLocales
-        - export LOCALE_ARCHIVE_2_27="${glibcLocales}/lib/locale/locale-archive"
-      script:
-        - nix-shell -I nixpkgs=https://github.com/NixOS/nixpkgs-channels/tarball/nixos-20.03 -p cachix --run 'cachix push ihaskell --watch-store &'
-        - >
-          nix-build
-          -I nixpkgs=https://github.com/NixOS/nixpkgs-channels/tarball/nixos-20.03
-          release.nix
-          --argstr compiler "ghc883"
-        - test/acceptance.nbconvert.sh result/bin/ihaskell-nbconvert