Set cwd to `get_source_dir(filename)` when running ghc-mod.

Fixes error that ghc-mod can't find a library in an executable in the following setup:

    name: mypackage
    library
      hs-source-dirs: src
    executable
      hs-source-dirs: apps
Show cabal warnings in the panel.

Before we only highlighted warnings, but did not show their text.

Thanks @eis in #haskell.
Add -v0 to cabal build when obtaining warnings.

This really only gets us the warnings / errors instead off progress output.
Slightly improve output panel spacing
Don't attempt to check & lint Cabal files.

Use fixed is_haskell_source() to determine if the current view is worth checking & linting as Haskell source.
Merge pull request #93 from sukhodolin/CabalFix

Don't attempt to check & lint Cabal files.
Properly implement 'inspect_modules' setting
Don't make build command dependent on autocomplete
Fix hdevtools absence not being detected correctly. Fixes #33

An exception was thrown when trying to show the error in a panel,
because there is no active yet at early startup.
Fix some whitespace
"Show symbol info": Put some quotes around symbols in error messages
README: Mention F4 instead of the custom error jump key bindings
README: Mention how to turn off the ModuleInspector
Unzip this package
README: Add cabal build systems section
README: Added link to hdevtools fork for windows

Fixed #98
Don't join ENV var paths with ':' on Windows
python 3 compatible compare
Merge pull request #109 from MasseGuillaume/master

python 3 compatible compare
Fixed #110