use download links instead of direct links. Make sure the correct security settings are used. refactoring of code
clean up event listeners
use unitOfWork in tests
fix test: added mock ClassMetaData object
fix unit test and run in processIsolation mode
fix tests for new onFlush PageListener method
Merge branch 'refs/heads/master' into upgrade_2.3

Conflicts:
	Controller/MediaAdminController.php
	EventListener/PageListener.php
get the cms running with new setup