SystemUI: Remove the dark pixel artifacts from the back arrow drawable

The arrow had some mostly transparent pixels that made it look
kind of like the device had defective pixels. Found by Cyril Mottier.

Change-Id: Ia78453868ebe7e3291d01c96b9beafc78ea3cdcc

Conflicts:

	packages/SystemUI/res/drawable-xhdpi/ic_sysbar_back_land.png
PackageManager: Restrict system packages to protected storage

Don't allow packages signed with the platform key to be
installed into user (or app) controlled storage

Change-Id: I7390b3bdf5289411f7a335c69635bed9f74bbfb3
Framework: Enable multi-user support for Notification light

Change-Id: I4fb84fdb0c9e1592c2a421011c303a789cde8c8c
SystemUI: HSPA+ Support

Add the ability to recognize HSPA+ by creating a separate case for HSPAP and
include new H+ icons.

Signed-off-by: Bajee11 <bajee11@gmail.com>
Change-Id: I889a28e4b4cb49862b291641df5a00388db87551
SystemUI: Make the HSPA+ drawables more consistent with the HSPA drawables

Though the older HSPA+ drawables are sharper, that makes them look
out of place in comparison with the HSPA drawables.

Change-Id: I76313ae0125b3a8fda928b240f33715e48f77867