Update the ic_grabber drawable with a holo version

Replaces the old gingerbread drawable with one that better
fits the holo design language. Also adds an xhdpi drawable.

Change-Id: I4365f7184f236c6e916015413f9a4f122b8e743c
Wi-Fi: Manage Wi-Fi AP priorities

AOSP has a basic LRU priority for Wi-Fi networks (last connected has more priority).
This changes added the ability of graphically set the priority of any of the configured
Wi-Fi networks through Settings -> Wi-Fi -> Advanced Settings -> Wi-Fi priority.

Change-Id: Ief590e799cdb7ef760b631d0b22d9719f867393f
Signed-off-by: Jorge Ruesga <jorge@ruesga.com>