Added support for OAuth2
Merge remote-tracking branch 'upstream/master'
Enabled authentication using OAuth2 (#2, #15)

This check in includes the following:

- Issue #2: Adds support for using OAuth2 for V1 API authentication
- Issue #15: Adds check for JSON credential files
Enabled localization API usage
Merge pull request #16 from aceybunch/master

Added support for OAuth2 (#2, #15)