Android build 32mb
Call the setting callbacks from the touchregions

Change-Id: I94e530e6035d63a15f1b8d571c28393172d162be
scale engine: add keep aspect ratio method

using a txt file name zoom.cfg contain only one string
"keep aspect ratio : on"
change "on" to "off" will disable the padding, no more black bars.
use sw_volume_control to do balance control on Android

Android audiomanager needs a mono value to set global streamVolume.
therefore, instant of parse l and r, This patch parse volume and balance.
and finish the remanding balance calculation in audiohw_set_volume().