Start collecting mobile radio activity from the radio.

Start collecting mobile radio activity from the radio.

Hook in to the new radio API to find out when the radio
is active and use that to track its state in batter stats.
We also still have the data being tracked from the kernel's
emulation, and continue to use that if we don't get data from
the radio.

Currently this monitoring is turned off until some issues
in the radio can be fixed that are providing bad data.

Also add a new API to get estimated drain and charge times.

Change-Id: Ifc4900fabb8f848f9cda361dce698664ea75f175