124 update storage for repose

Neither Deuce or any storage drivers should save any user credentials or storage URL.

All requests provide token in the header x-auth-token and storage URL in the header x-storage-url, which should be filled up by Repose instead of the users.   Unittests reflect the requests behind (/after) Repose.  


x-storage-url is not universally required, but when x-storage-url required, x-auth-token and x-project-id are required too.  Can I rename authtokenhook.py to a generic name, like "storage hook"?