SoundRecorder: only look for source files in src

gen/ sub directory generated by IntelliJ doesn't play nice unless we
only compile from src.

Change-Id: I32be9b7f2e330610dde3e2658f547572e30ee0e6
Signed-off-by: Roman Birg <roman@cyngn.com>
Merge remote-tracking branch 'cm/cm-11.0' into HEAD