Changed definition of keyword.

Now `e` and `w` and `*` work on CSS property names, hexadecimal colours, and hyphen-separated-variables. Wee!

Also, the definition of a Stylus comment as `//\s` was annoying me (sometimes I'm lazy and just want to comment-out one property!), but I'm too unexperienced with Vim syntax highlighting to make it work properly. I _think_ that the regions are messed up concerning `cssFuncVal`. All I want is for `//` to not start a comment in `url(...)` regions!