Fix doc formatting to avoid missing spaces.

Before: 

![doc-formatting-fix](https://cloud.githubusercontent.com/assets/4745181/2812657/2c2e5c24-ce67-11e3-8762-75fb661eca3c.png)

This pull request fixes this issue by adding a space at the beginning of every line but the first on long docstrings, as that was causing this bad formatting.

I have a feeling that this issue affects other parts of the famous docs as well.

No documentation content was changed in this fix.