screenrecord: Add audio support

Adds audio recording to the screenrecord system. Note that
while recording, the audio is muted from the device output,
and that the audio volume is controlled separately (so make
sure to turn up your volume if you hear nothing).
Audio from the microphone can also be recorded by adding
--microphone to the command line.

Change-Id: I97dfcaf3d93b786c5466e1f4215549e3d015bcf0
fix screenrecord abort issues

Change-Id: I95ae71e49506d3dfa7df691f0a9b6464ff691ff1
Merge "screenrecord: Add audio support" into android-4.4
Merge branch 'android-4.4' of https://github.com/omnirom/android_frameworks_av into android-4.4