Since we cannot rely on the API to be stable upstream, let's start
making the pkg-config, library, and include dir have a version suffix.
This will allow different downstream projects depending on us to
independently switch versions without packagers having to jump through
hoops.
This new lib contains the bare minimum to implement an iSAC encoder and
decoder.
The webrtc files have been copied from the revision as the existing
imported files (c8b569e0a7ad0b369e15f0197b3a558699ec8efa).
