Improve C# highlighting for the Tomorrow styles

Class and method names were being colored with the same color as comments, which was a little bit confusing.

I tried some other colors, but ended up choosing *Aqua* for the job, which I believe was a good fit for all variations.

### Comparison Screenshots

*Before* on the left, *after* on the right.

`tomorrow`:

![image](https://cloud.githubusercontent.com/assets/126538/4691300/82d8647e-5711-11e4-886f-f74ca3fbb951.png) ![image](https://cloud.githubusercontent.com/assets/126538/4691320/8c912d6a-5712-11e4-9d9f-02ccd6c9fc2f.png)

`tomorrow-night`:

![image](https://cloud.githubusercontent.com/assets/126538/4691337/5c55cc54-5713-11e4-8722-0305e12f9033.png)![image](https://cloud.githubusercontent.com/assets/126538/4691351/d51a8c88-5713-11e4-9413-9d0eb7ca4bdb.png)