(Minor) Add whitespace to list of optimizations in docs. 

![screen shot 2013-05-26 at 6 30 20 pm](https://f.cloud.github.com/assets/54067/566122/10811e24-c66d-11e2-9f5e-7991bbf6a719.png)

Screenshot shows garbled list. Adding whitespace to the source's list fixes it (after converted to PDF).