* Activate restricted_data_cache on inmemory cache
* Use ElementCache in rest-api get requests
* Get requests on the restapi return 404 when the user has no permission
* Added async function for has_perm and in_some_groups
* changed Cachable.get_restricted_data to be an ansync function
* rewrote required_user_system
* changed default implementation of access_permission.check_permission to
check a given permission or check if anonymous is enabled
Also fixt the case, where an anonymous user connects to the websocket connection.
Also added a function anonymous_is_enabled() to see, if the anyonmous user is enabled.
Added pip freeze to travis to see installed versions.
* Add caching support to users/group
* Add a function has_perm that works with the cache.
* Removed our session backend so other session backends (without the database) can be used
* Second websocket channel for the projector
* Removed use of projector requirements for REST API requests.
Refactored data serializing for projector websocket connection.
* Refactor the way that the projector autoupdate get its data.
* Fixed missing assignment slide title for hidden items.
* Release all items for item list slide and list of speakers slide. Fixed error with motion workflow.
* Created CollectionElement class which helps to handle autoupdate.
- Used raw SQL for createing default projector during inital migration.
- Removed default_password and hidden agenda items from autoupdate data for some users.
- Removed old get_collection_and_id_from_url() function.
