t0lte: user configureable voice/streaming volumes [1/2]

This uses 4 files to store the voice volume:
incall_earpiece, incall_headphone, incall_speaker, incall_bt, and 2
for streaming volume: out_speaker, out_headphone located /data/local/audio.

Change-Id: I4269dc65d48e04b5e908b20704128241683d5a80