Create Account and Message types
Create SMS type and move Message methods there
Updated to google style API package

Sorry for not commiting things as I went. They got all jumbled up. I
incorporated the README changes and comments.

API structure is based on
http://godoc.org/github.com/google/go-github/github
* development:
  Updated to google style API package
  Create SMS type and move Message methods there
  Create Account and Message types
Merged in new structure.
Merging is not always simple... :)