Remove windowmanager hacks form the incubation controller.

Tie incubation directly to wether animations are running
or not. When animations are running, we incubate for
a third of a frame only. When animations are not running
we incubate whatever is left as the scene is anyway idle.

Change-Id: I88c9248e9d7b3b35c99fca52aeb9c681d1b4a306
Reviewed-by: Martin Jones <martin.jones@nokia.com>