removed all dependence on NodeOutputs

If Nodes only have the one output, we don't need to do so much differentiation
between them. Previous iteration used outputs as like a distinct function
within a Node (e.g. length output would return one result, buffer output would
produce a different result - each run different code to produce their results).
Now in this iteration, it's more accurate to say a Node is just one function
(which seems more appropriate for a node system anyway).

app/render/backend/audio/audioworker.cpp

@@ -9,15 +9,3 @@ QVariant AudioWorker::FrameToValue(FramePtr frame)
 {
   return frame->ToByteArray();
 }
-
-bool AudioWorker::OutputIsAccelerated(NodeOutput *output)
-{
-  Q_UNUSED(output)
-  return false;
-}
-
-NodeValueTable AudioWorker::RunNodeAccelerated(NodeOutput *output)
-{
-  Q_UNUSED(output)
-  return NodeValueTable();
-}

app/render/backend/audio/audioworker.h

@@ -11,10 +11,6 @@ public:
 protected:
   virtual QVariant FrameToValue(FramePtr frame) override;
 
-  virtual bool OutputIsAccelerated(NodeOutput *output) override;
-
-  virtual NodeValueTable RunNodeAccelerated(NodeOutput *output) override;
-
 private:
 
 };