Batch alarms to reduce device wakeups

The default Alarm Manager behavior for KLP+ apps will be to aggressively
coalesce alarms, trading exact timeliness of delivery for minimizing the
number of alarm-delivery points, especially wakeup points.

There is new API in AlarmManager, setExact() and setExactRepeating(),
for use by apps that absolutely *must* get their alarms at a specific
point in time.

Bug 9532215

Change-Id: I40b4eea90220211cc958172d2629664b921ff051