Better haml support, with parentheses coloring, auto close parentheses, brackets,
curly braces, quote, double quote, backtick, ruby interpolations, etc.
Only support haml extension, remove sass extension.
Will be based on http://haml.info/docs/yardoc/file.REFERENCE.html
- [x] colorize parentheses attributes
- [x] ruby highlighting (=, -, etc)
- [ ] autocomplete stuff
- [x] fix broken highlight with hyphen
- [x] autoclose quote backtick ruby literal
- [X] snippets
- [ ] refactor, a lot of redundancies in the syntax
- [ ]
:preserve filter doesn't work correctly yet