Audio HAL

Adding headers and test for Android Audio HAL.

This is useful in case you want to control both PCM and mixer using the HAL directly (without AudioFlinger).

Test done with Galaxy Nexus, Nexus 4 and Nexus 10.

teroot@ubuntu-phablet:~# test_audio 
found ro.hardware for mako
found ro.product.board for MAKO
found ro.board.platform for msm8960
__pthread_gettid -2
found ro.hardware for mako
found ro.product.board for MAKO
found ro.board.platform for msm8960
found persist.audio.handset.mic for dmic
found persist.audio.fluence.mode for endfire
ACDB init open file failed
[ACDB Init]->File is not found on the system
[ACDB Init]->ACDB init success!
found ro.baseband for mdm
found ro.board.platform for msm8960
found ro.baseband for mdm
Audio Hardware Interface initialized.
Master Volume: 0