NSManagedObjectContext+CDKSaveObserving added
CDKObserving category added
A CDKObjectControllers fetch request is now publicly available

Signed-off-by: Felix Gabel <felix@orderbird.com>
CDKObjectsController renamed to CDKFetchController

Signed-off-by: Felix Gabel <felix.gabel@me.com>
all old CDKObjectsController references replaced

Signed-off-by: Felix Gabel <felix.gabel@me.com>