Everything: psr-4 namespacing, remove defunct methods, no more oauth
Api: Remove _delete, _put, and _post methods
README: Update documentation and installation instructions
Everything: Unit tests. Rename Api class to Client since that makes more sense.
Client: Remove redundant comment
Merge pull request #23 from markdunphy/remove-oauth

Everything: Clean up a little, remove OAuth, remove non-GET requests, add PSR-4 autoloading, unit tests.