Initial documentation and developer's guide

I'm punting on JSDoc for now for the api documentation.  We will have to get that working later.  I will also work on an introduction into the api conventions such as a description of the core objects and code organization.  For now, I think this is a good start.

I also added hooks to update readthedocs.org automatically.  See the current output from this branch here http://geojs.readthedocs.org/en/documentation/.