support for alsa compress API

Submitted by Qais Yousef

Link to original bug (#743192)

Description

As per the thread on gstreamer mailing list [1], I'm looking at adding support for alsa compress API. Any direction on what's the advised method of adding this support? To start up I'm wondering whether the support should be an extension of existing alsasink component or whether to add it as a separate component (which I think is the better option).

Thanks,
Qais

[1] http://gstreamer-devel.966125.n4.nabble.com/ALSA-Compress-Offload-support-td4670153.html