Remove Nexus libaudio version

Change-Id: I8f902a4f012d4ec16534ae25a9383b95e75d0ee5
Implement basic ALSA audio driver

* Basic functionality tested - speaker out, microphone in
* Implement basic audio_policy.xml
* Implement basic mixer_paths.xml configuration for Broadcom ALSA device
* Install generic media_codecs.xml to fix software encoding/decoding
* Implement symlink workaround to ensure loading of /etc/media_codecs.xml and
  /etc/media_profiles.xml (kernel bug?)

Based on ASUS grouper driver:
https://github.com/CyanogenMod/android_device_asus_grouper/tree/cm-11.0/audio

Change-Id: I55e35950d2c26ae64bbd2b0b6550bf715933f9ad