Merge branch 'mediastreamaudiosource'

* mediastreamaudiosource:
  Adds basic audio in demo.
  Only copies inputs if there's a real input node in front of the jsnode.
  Adds mediastream-based audio input, which replaces mike.js.. Fixes errors in Freeverb (but it sounds broken).
  Adds temporary way to insert nodes before and after the Flocking node.
Adds simple audio in playback demo.
Removes pre-Web Audio Firefox audio strategy.
Still-sketchy implementation of multiple audio inputs.
Introduces Web Audio Device Manager and refactors audio strategy.