Haskell support and fix for non-STDIN inputs

1) Adds support for linting Haskell files.
    Note: Only has support for where hlint is on $PATH and on OS X w/Haskell Platform, but this is easy enough remedied once it's being used.

2) Fixes an issue with the likes of INPUT_METHOD_TEMPORARY_FILE. If this method or INPUT_METHOD_FILE was used, without an argument, it wouldn't work. This way if there's nothing specified it defaults to '{filename}'