[SVN] CSS appearance & adjusting element names

[Chris Thomas]

At the moment, in every theme except Pastels on Dark, CSS files are  
not particularly attractive.

While it's probably true that, like Pastels on Dark, each theme  
should contain specialization for CSS, it would be nice if the  
appearance in a simple theme was more palatable. Right now, the  
elements are indistinct, so the whole text runs together visually.

If I make two changes to the language def, the appearance of the non- 
CSS-specialized themes improves:

     support.constant.property-name.css -> support.type.property- 
name.css
     constant.other.css-units -> keyword.other.css-units

Wouild anyone be unhappy if I checked these changes in (I'd also  
commit a similar adjustment to Pastels on Dark to preserve the  
existing style)?

Chris