Added travis build script.

.travis.yml

@@ -0,0 +1,27 @@
+# NB: don't set `language: haskell` here
+
+# The following enables several GHC versions to be tested; often it's enough to test only against the last release in a major GHC version. Feel free to omit lines listings versions you don't need/want testing for.
+env:
+# - GHCVER=6.12.3
+ - GHCVER=7.4.2
+ - GHCVER=7.6.3
+ - GHCVER=7.8.2 # see note about Alex/Happy
+# - GHCVER=head  # see section about GHC HEAD snapshots
+
+# Note: the distinction between `before_install` and `install` is not important.
+before_install:
+ - travis_retry sudo add-apt-repository -y ppa:hvr/ghc
+ - travis_retry sudo apt-get update
+ - travis_retry sudo apt-get install cabal-install-1.18 ghc-$GHCVER
+ - export PATH=/opt/ghc/$GHCVER/bin:$PATH
+
+install:
+ - cabal-1.18 update
+ - cabal-1.18 install --only-dependencies --enable-tests
+
+# Here starts the actual work to be performed for the package under test; any command which exits with a non-zero exit code causes the build to fail.
+script:
+ - cabal-1.18 configure --enable-tests -v2  # -v2 provides useful information for debugging
+ - cabal-1.18 build --ghc-options=-Werror  # this builds all libraries and executables (including tests/benchmarks)
+ - cabal-1.18 test
+ - cabal-1.18 check