Feature regexp syntax

The additions includes better support for inline regexes. Note that all divisions/regexes expressions have been tested against the CoffeeScript compiler so it should never highlight inappropriately divisions as regexes and vice versa.
For inner inlined regexes I reused the `source.js.regexp` grammar, but for the heregexp syntax I had to modify it a bit and include it in the CoffeeScript grammar to reuse the interpolated coffee rule.

Below a render of my sample file using the default Solarized dark theme:  
![Coffee Regexes Sample](http://i.imgur.com/8s7D9Dp.png?1)