Fix documentation compilation warnings and improve formatting of output

There were some warnings being output when I was compiling the docs. This change fixes those warnings. It also removes the documentation of the default types, which already gets included automatically and was wrong because not kept in sync with the function signature. Finally, I changed the formatting to the Sphinx formatting. This looks much better in the compiled documents, but does make the source a bit harder to read. I've seen other folks suggesting it might be easier to follow the Google style guide (http://google-styleguide.googlecode.com/svn/trunk/pyguide.html#Comments) and ignore the Sphinx formatting. I'll let you guys decide whether you like that last change or not. I've attached screenshots of the before and after of the compiled docs.

![before](https://f.cloud.github.com/assets/322311/785909/1c5f80aa-ea94-11e2-93c9-ff778f02fe51.png)
![after](https://f.cloud.github.com/assets/322311/785910/1c65c88e-ea94-11e2-9e69-7c9d1ace10ee.png)