Add tests and functionality

/cc @sshillo @nbryan @ciniglio

Added team america, and hipchat niceties 
Dood! You removed tests, and failed to name the person who came up with the idea and wrote the base code!? ELL-AA-EMM-EEE!

This may introduce breaking changes, because field functionality was buried in the API code... why?

- moved fields functionality into the gem (why was it ever anywhere else)
- added documentation
- added tests
- added attribution (lame!)
- removed active support, it was whining a lot