Syntax highlighting for guides.

Pull Request #379 was originally opened to add syntax highlighting to one of the guides.

This PR correctly implements syntax highlighting, and adds it to all guides where appropriate.

Before:

![before](https://f.cloud.github.com/assets/65057/1609017/1cace25c-5527-11e3-907f-769d03761d05.png)

After:

![after](https://f.cloud.github.com/assets/65057/1609018/1f40df1e-5527-11e3-99d2-8ca11f5d7f30.png)