Remove @return occurrences in the API documentation [ci skip]

In the API documentation there are several cases where some documentation/editor hints are displayed to the user and they look kinda out of place.
 
![screen shot 2014-05-07 at 6 26 38 pm](https://cloud.githubusercontent.com/assets/604618/2905379/ae4e1d4e-d604-11e3-9451-c94de0a73d8f.png)

I think that where those occur, the documentation is good, so I just removed them. If those were there for a reason, you can ignore this.

Have a good day!