Themes: Use first asset entry for lockscreen wallpaper

The current implementation assumes the wallpaper will be named
either wallpaper.png or wallpaper.jpg.  If this is not the case
the wallpaper is not applied.  This patch implements the lockscreen
wallpaper the same way that the regular wallpaper is done.

Change-Id: I9f3dd299c1e61158fa53c163f7e42e21e2f9b1dc
Themes: Use default_wallpaper for HOLO lockscreen wp

Change-Id: I9c7fd29c99d13e811993eb9b3b045010431ccad0
Themes: add ability to theme quick settings battery tiles

This is to make the battery tiles more uniform to the rest
of quick settings and also allow the background to be themed

http://i.imgur.com/AA5bkMK.png

Change-Id: Iec03572a0fa3619d2652f30b6c260a278ed0c86b

Conflicts:
	packages/SystemUI/res/layout/quick_settings_tile_battery.xml
	packages/SystemUI/res/layout/quick_settings_tile_dock_battery.xml
	packages/SystemUI/src/com/android/systemui/quicksettings/BatteryTile.java
Themes: Update LoadedApk resources.

Instead of creating a new LoadedApk when resources are not up to
date, we use the existing LoadedApk but recreate mResources.

Change-Id: Ic1ad810863d03c2cedc751c9e84dd7c954daf3d7
Themes: Add icon previews to ThemesContract

Change-Id: Icbfbee3404702a29881ad4933721d8beb39bef30
Themes: Style, boot animation, and wallpaper previews

Change-Id: I2b367bf5336c03f2a4972a05b68922065cd4a701