ref #1476 [Implement audio in App Design v2]

http://redmine.named-data.net/issues/1476
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- implemented audio sender
ref #1476 [Implement audio in App Design v2]

http://redmine.named-data.net/issues/1476
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- implemented: audio renderer , audio capturer, audio consumer, audio
playout classes
- updated audio sender class according to the new namespace
- updated pipeliner for optional use of key namespaces
- updated playout base class
- extracted new interface: IRenderer
- updated tests
'issues/1476-audio-v2' -> 'dev'