Set foreground priority for shutdown receivers.

The broadcast of ACTION_SHUTDOWN has a timeout of 10 seconds. To
reduce the risk of hitting the timeout and speeding up the
shutdown sequence in ShutdownThread we set the priority of the
BroadcastReceivers to FLAG_RECEIVER_FOREGROUND.

We have seen that this change reduces the shutdown time when
the system is under heavy load.

Change-Id: I22cbf6af8cf6fc4bdefaa1c3da8a7eed7e7b7674
SectionIndexer: Update Javadoc for ExpandableListAdapters

SectionIndexer could be implemented by ExpandableListAdapters
that considers groups and sections as synonymous and such
adapters have to account for collapsed groups and should
return appropriate section/position.

Change-Id: If0dec268da8fa30bd26f4d0aaad7e644a9944313
Merge "Set foreground priority for shutdown receivers."
Merge "SectionIndexer: Update Javadoc for ExpandableListAdapters"
Add Colemak keyboard layout

Change-Id: I203b92e56522bc7b3014195d5d83dc1fdb3cab15
Merge "Add Colemak keyboard layout"