Add network usage stats to status bar (1/2)
PS2:
Get the time delta between updates and use that to show
average bytes per second.

Change-Id: I63771220333a32063f675e6fc38c9aadb6de4274
NetStats: Don't update stats when screen is off

Also moved registering of broadcast receiver and settings
observer to onAttachedToWindow() and unregistering to
onDetachedFromWindow() to avoid these being leaked.

Change-Id: Ia131a0db65c4c762b7f28493e812f9fb21358a27
Network stats custom colors (1/2)

Change-Id: I3c95a70273b111c7776f395f7baa60a77cea95dd

Conflicts:
	core/java/android/provider/Settings.java
Network stats: Hide if there's no traffic (1/2)

Change-Id: I8b770c7ad803c063cf995e5f88c8f44e0eeae86a