Cleaning Ghcjs.hs a little bit
Removing debug statements & moving installNativeHooks
Moving DriverHook to GhcjsHooks and some file utility functions to Compiler.Util
Tidying up 'generateNative' a little bit
making mkGhcjsOutput safe

tail fails on an empty list, which means that mkGhcjsOutput might have
been failing on files without extensions
Adding .jsexe files to the ignore list
Exporting compilationProgressMsg from Compiler.Utils

Cannot move compilationProgressMsg and ghcjsSrcSpan fully to the
Compiler.Utils modules because the linker also yield messages
Introducing partition_args_js in Compiler.Utils

- Also Compiler.Util -> Compiler.Utils
Moving setGhcjsPlatform to Compiler.GhcjsPlatform
Merge branch 'master' into cleanup
Moving 'runGhcSession' to a separate module