Added G+ community to README
Incremental updates to providers
RefreshTokenGrant
Refactoring towards spec compliance, step 1.
Fix a typo in the code that converts arguments from bytes to unicodes.
Fix issue #86 by adding `nonce` and `timestamp` arguments to Client
constructor.  In get_oauth_params(), use the explicitly provided nonce and
timestamp if given, otherwise generate them.
Merge pull request #87 from warsaw/issue86

Issue86
Experimental default unicode conversion (#53, #68, #86)