Fixed accessibility issues with quick settings

The dual mode tiles now have better accessibility descriptions,
where the label is now seperate from the clickable button.
Also fixed an anouncment problem with the battery indicators.
Finally fixed an issue where GPRS null was anounced when no signal
was available.

Bug: 15682124
Bug: 15696954
Change-Id: Ica2b70173e64d51747b100d0b686875fc8076e6f