Fixes and CSS support

- Removed regular expressions since they break YCM previews
- Extends the CSS snippets so you can use CSS snippets in Sass/SCSS
Hm no, the commit is fine. Check the below screenshot for ```line 5``` right below your comment.
![screen shot 2014-08-31 at 19 28 53](https://cloud.githubusercontent.com/assets/265947/4102618/566407ca-3134-11e4-8118-6ed3980751c1.png)

Regarding the ```b``` option removal: I had forgotten the meaning of ```b```; thought white space at the beginning of the line would actually prevent the snippets from triggering. Will fix that in another commit.