Add var for javascript, update various javascript colors

I'm not the best with less (or css for that matter) so I might not have changed these values in the right place. But here is a before shot (compared with vim):
![screenshot 2014-11-22 21 38 12](https://cloud.githubusercontent.com/assets/3849309/5156885/b3b9b466-729c-11e4-8999-efc82f8493fa.png)

And here is an after shot (also compared with vim):
![screenshot 2014-11-22 23 10 47](https://cloud.githubusercontent.com/assets/3849309/5156889/dad2efcc-729c-11e4-8fe1-db180f31e620.png)