Added droid-util headers for 4.4

Copied from droid-util-42.h
Recognise AUDIO_DEVICE_OUT_PROXY
Add AUDIO_DEVICE_OUT_PROXY in output device conversion table
Recognise AUDIO_OUTPUT_FLAG_COMPRESS_OFFLOAD, AUDIO_OUTPUT_FLAG_NON_BLOCKING
Recognise AUDIO_CHANNEL_IN_FRONT_BACK
Use speaker as default device
Do not fail while parsing speaker_drc_enabled tag