Adds Coinbase::OAuthClient which supports request authenticated with OAuth 2.
Add common authorization flow.
OAuth client WIP
Rewrote OAuthClient tests
Added refresh! method
Added some docs
Removed dependency on respec-mocks
Fixed typo
Merge branch 'use_query_params' into oauth2
Use query params for GET and DELETE in OAuthClient
Merge branch 'use_query_params' into oauth2
Depend on specific version of oauth2
Tweaked README
Merge pull request #36 from coinbase/oauth2

Added OAuth Support