Remove TravisCI configuration file

.travis.yml

@@ -1,31 +0,0 @@
-sudo: false
-language: c
-
-env:
-  - ARGS=""
-  - ARGS="--resolver lts-2"
-  - ARGS="--resolver lts-3"
-  - ARGS="--resolver lts-5"
-  - ARGS="--resolver lts-6"
-  - ARGS="--resolver lts-7"
-  - ARGS="--resolver nightly"
-
-addons:
-  apt:
-    packages:
-      # Needed for GHC.
-    - libgmp-dev
-
-cache:
-  directories:
-  - $HOME/.stack
-
-before_install:
-  - mkdir -p ~/.local/bin
-  - export PATH=$HOME/.local/bin:$PATH
-  - travis_retry curl -L https://www.stackage.org/stack/linux-x86_64 | tar xz --wildcards --strip-components=1 -C ~/.local/bin '*/stack'
-
-script:
-  - stack build --install-ghc --test --bench --no-run-tests --no-run-benchmarks --pedantic
-  - stack test
-  - stack bench