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
Merge pull request #44 from CyanogenMod/cm-11.0

frameworks/base: Update quick launch shortcut icons/resources