furthered development of audio renderers

Mostly reimplementing functions from other workers to produce audio samples

app/render/backend/audiorenderworker.cpp

@@ -0,0 +1,22 @@
+#include "audiorenderworker.h"
+
+AudioRenderWorker::AudioRenderWorker(DecoderCache *decoder_cache, QObject *parent) :
+  RenderWorker(decoder_cache, parent)
+{
+}
+
+void AudioRenderWorker::RenderAsSibling(NodeDependency dep)
+{
+
+}
+
+bool AudioRenderWorker::InitInternal()
+{
+  // Nothing to init yet
+  return true;
+}
+
+void AudioRenderWorker::CloseInternal()
+{
+  // Nothing to init yet
+}