Remove username and password from configuration.

It is possible that we will want to re-enable username/password
authentication, but this will require further code changes anyway so
removing for now.
Switch to using client_credentials strategy.

This strategy allows you to authenticate with just the client_id and
client_password. However, it normally limits access to a basic level -
nothing that is per-user.

The Zoning API has been configured to allow full access to 'trusted'
applications without authentication. This means that for trusted
applications, the client_credentials strategy gives the same level of
access as the other strategies.
Hide internal errors as '500 Internal Server Error'
Update Readme
Version bump to 0.0.2
Remove protocol config setup.

Leaving the configure block because it might be needed for other tests.
Merge pull request #2 from opencounter/oauth

OAuth2 Refinements