OC_Cache namespace changes and add UserCache to server container.

Refs #4863
Add legacy wrapper
Use new emitter system
Merge branch 'appframework-master' into public_cache

Conflicts:
	lib/public/iservercontainer.php
	lib/server.php
Note to self: Test before pushing!!!
Note to self 2: Do as you preach. Test!
updating php docs
Merge pull request #4886 from owncloud/public_cache

Public cache etc.