Add the ability to specify the URI against which OAuth2 tokens are validated in the GoogleOAuth2 constructor.
Revert the change to token.dart - the validation function is public, which means it would be a breaking change even with all callsites within the project being updated.
Merge pull request #62 from dgresham/token-uri

Add the ability to specify the URI against which OAuth2 tokens are validated in the GoogleOAuth2 constructor.