make Haskell tests return a proper exit code on failure
add a script to run all of the haskell tests
Merge pull request #775 from etrepum/fix-haskell-tests

make Haskell tests return a proper exit code on failure
teach travis how to test the Haskell code
Merge pull request #776 from etrepum/haskell-tests

Test all Haskell exercises with Travis-CI
Add rough draft of team feature
Ensure comments are sorted. Fixes #718.
Fix typo
Order requires in alphabetical order