Remove unused handlers.
Fix rpcSend to properly target group and data.

Bad copy paste from _rpcSend.
Emit the metadata as well.

I'm not a huge fan of this, but sometimes its necessary and it'll help
keep from having to restructure things too heavily for internal use as
well.
Add example to rpcSend documentation.
Add rpcReceive for responding to RPC requests.
Merge pull request #12 from nubs/master

Finish up RPC calls