Near complete documentation of packet types and payloads 

Documentation is starting to get pretty lengthy, not sure how well the Github wiki stuff works. Also, hope you don't take offense to some of the language edits. For example, Get/Set seem to be more natural vs. Request/Receive or Request/Set.

I also renamed some packets and payloads to align with the "official" app implementations. It's not ideal in some cases but it'll lessen confusion when the official SDK lands. (Assuming the app implementations are right... <g>)