Merge branch 'master' into develop
Update 'lib/oauth2.js'

- Add debug output.
- Correctly handle unauthenticated users.
- Forward errors to application.
- launch test with `DEBUG` set to `oauth2:*`.
Update 'test'

- Fix deprecation warning.
- Add debug trace.
Update 'README.md'
Update 'package.json'

Remove the DEBUG env variable setting before launching the test
application.This is up to the developer to set the variable like he
want it to be set.
Update 'lib/oauth2.js'

Prevent middleware actions on the callback route.
Merge branch 'develop'