Merge branch 'release/2.1.0'
Cleaned up README
Merge branch 'release/2.1.0'
Merge tag '2.1.0' into develop

Final fixes for v.2.1.0  (2013-09-13)

  - Adds /source/log call
  - Updated /source/create call to comply with latest version of the API
  - Removed JSON gem - now dependant on Yajl-Ruby for JSON parsing
  - Added license info to gemspec
  - Fixed edge case when passing refresh token to authentication with G+ API
  - Fixed /source/get call