GlowPadView : Re-enable magneticTargets

Re-enable magneticTargets and add logic to make it
compatible with lockscreen shortcuts.

Change-Id: I523141f03566804888fde08a116f73ea62ca523e
SystemUI: always use transparent notification shade

Devices with less than 512MB of memory have a solid
black notification shade. Remove the isHighEndGfx()
check to force a transparent notification shade on
all devices.

Change-Id: I9a68a2a8b0d36685f8899f3bbed43bb6bccb47b1