Be more robust when attempting to parse the subscription ID.

E.g. emergency calls have the ID 'E'.

Change-Id: I1669c3fe702883b05db9c02d42cc98a6c8f44b79
Base InCallUI theme on material theme.

Not sure what CAF thought when they changed it to Holo...

Change-Id: I2bdc692b782dda8730e9dfb79603951470108dac