Enable Authorization through statusdb. 

- reorganization, moved mainhandler to util from status_app
- reorganization, moved login handler to authorization.py
- Added authorization in statusdb to login handler
- Secured all sensitive handlers by making them inherit from SafeHandler
- Added buttons for login and logout
- Added a fancy page for unauthorized users.
- Added a possibility to start server in test mode, not default, so that integration tests work without changes.