Revert "Remove dock home support."

This reverts commit 7c135205f2f4c192299ad0215276e9e481bccaa5.

Conflicts:

	policy/src/com/android/internal/policy/impl/PhoneWindowManager.java

Change-Id: I9b2c4eebaab87a669b42681e70ec5324dadf7f6d
Revert "Re-implement magnetic targets"

This reverts commit b75eace653afe11913fa35517214c071ebdbd92a.
SystemUI: option to toggle dimming of the notification shade (1/2)

Allow the user to enable/disable dimming of the notification shade
pulldown. Check isHighEndGfx() to respect the default setting that
the device currently supports.

Users on low-end device may want to have this feature, while users
on high-end devices may want to disable it (possible battery life
savings and what not).

Change-Id: Id62d924dd9e0efea3849ef52eabafb7dd3d94e03