Framework: Notification Shortcuts (1/2)

This feature adds shortcut icons to the bottom of the notification
drawer.
Preview: http://goo.gl/hSHQM

Feature highlights:

- Select up to 16 different shortcuts
- Link to any application or activity
- Use the default application icon, pick from an image or pick from
included stock icons
- Colorize application/image icons as well as stock
- Hide carrier label

Change-Id: I9a2770c560c765453549b8f99598afbbb24e663a