code block styles

These are changes based on my general observation and personal taste. Please feel free to provide your own opinion.

# Before

![apidocumentationcodestylingbefore](https://f.cloud.github.com/assets/486512/1480352/eb2f4800-46a8-11e3-8af6-fd53f4975614.png)

# After

![apidocumentationcodestylingafter](https://f.cloud.github.com/assets/486512/1480354/ef1568dc-46a8-11e3-95af-7673fa6d21bd.png)