PassThroughNode = function(audiolet, numberOfInputs, numberOfOutputs) {
    AudioletNode.call(this, audiolet, numberOfInputs, numberOfOutputs);
}
A specialized type of AudioletNode where values from the inputs are passed
straight to the corresponding outputs in the most efficient way possible.
PassThroughNodes are used in AudioletGroups to provide the inputs and
outputs, and can also be used in analysis nodes where no modifications to
the incoming audio are made.

@constructor
@extends AudioletNode
@param {Audiolet} audiolet The audiolet object.
@param {Number} numberOfInputs The number of inputs.
@param {Number} numberOfOutputs The number of outputs.