Subject: Features

Adds support for AudioSocket, a very simple bidirectional audio streaming
protocol. There are both channel and application interfaces.

A description of the protocol can be found on the referenced wiki page. A
short talk about the reasons and implementation can be found on YouTube at
the link provided.

ARI support has also been added via the existing "externalMedia" ARI
functionality. The UUID is specified using the arbitrary "data" field.

Wiki: https://wiki.asterisk.org/wiki/display/AST/AudioSocket
YouTube: https://www.youtube.com/watch?v=tjduXbZZEgI
