Fix broken ghc-mod

cwd parameter to ghc-mod was broken.
Cleanup.
Minor fixes
Fixed minor bug
Get symbol type with hdevtools on module loading if possible
Fix for Sublime Text 3
Fixed different string types in Sublime Text 2 and 3
Grabbing definitions for type/newtype/data
Fixed typo
Fixed browse module within symbol info command
Fixed, dict_values doesn't support indexing
Merge pull request #34 from kolmodin/patch-1

Fix broken ghc-mod execution
README: Improve optional dependencies section
README: Add short usage
Fixed docs: where haskell-docs are used
Some fixes for Python 3
Encode/decode of call_and_wait output for Python 2/3
README: note about context menu
Fixed hdevtools initializing, but it still needs to be improved
Changed hdevtools init one more time