Revert "Active Display: check if recievers and listeners are registered"

This reverts commit b1faa38cb6c9cd196ef7fde3d1e1621fa66968d8.
Active display: Unify (un)registering callbacks and add proper checks

Change-Id: Ie4c4660a54d2c60831f7a3bcc66b3a9ca1d035f2
Active display: Don't register proximity if pocket mode not used
[log]

Change-Id: I6f27bd86e2dbe2bc14b88acb94668a593590853a
Active display: Option to change display timeout…
…[1/2] [log]

Change-Id: I3e0d9d05ddf3892b0223c012b5420bbcf4e3b6e1
Active display: Add threshold to proximity sensor…
… [log]

Display will only be activated if the proximity sensor is covered for 5 seconds or more.

Change-Id: I0e9744d82884fc7aa7671ca8c93f49430359fee6

Conflicts:
	packages/SystemUI/src/com/android/systemui/statusbar/policy/activedisplay/ActiveDisplayView.java