frameworks/base: Update quick launch shortcut icons/resources

Update the existing icons and add "xxhdpi" versions created
from a vector template. This commit cleans also the resource
files a bit up.

Screenshot: http://goo.gl/6CrMYr

Change-Id: I45abee5cf13cd239eb5b4402019afac28d6d5952

Conflicts:
	core/java/com/android/internal/util/cm/NavigationRingConstants.java
	core/java/com/android/internal/util/cm/NavigationRingHelpers.java
	core/res/res/drawable-hdpi/ic_navigation_ring_killtask_activated.png
	core/res/res/drawable-hdpi/ic_navigation_ring_killtask_normal.png
	core/res/res/drawable-mdpi/ic_navigation_ring_killtask_activated.png
	core/res/res/drawable-mdpi/ic_navigation_ring_killtask_normal.png
	core/res/res/drawable-xhdpi/ic_navigation_ring_killtask_activated.png
	core/res/res/drawable-xhdpi/ic_navigation_ring_killtask_normal.png
	packages/SystemUI/src/com/android/systemui/cm/ActionTarget.java
Themes: Add icon previews to ThemesContract

Change-Id: Icbfbee3404702a29881ad4933721d8beb39bef30
HeadsUp: Add heads up blacklist options. (1/2)

Change-Id: If9e5eed658871400b3c21d9354262e0887bc592e