Bug 865247 - Part 1: Give MediaInputPort the notion of an input and output port number; r=roc
Bug 865247 - Part 2: Tell MediaInputPorts about their input and output ports; r=roc
Bug 865247 - Part 3: Add a ProduceAudioBlock overload to handle simultaneous processing of multiple input and output ports; r=roc

The ObtainInputBlock API is also changed to create an input block for one input
block at a time.  An array of these input blocks is then sent to
ProduceAudioBlock for processing, which generates an array of AudioChunks as
output.

Backwards compatibilty with existing engines is achieved by keeping the
existing ProduceAudioBlock API for use with engines with only a maximum of one
input and output port.
Bug 865247 - Part 4: Implement ChannelSplitterNode; r=roc
Bug 865248 - Implement ChannelMergerNode; r=roc

--HG--
rename : content/media/webaudio/ChannelSplitterNode.h => content/media/webaudio/ChannelMergerNode.h