#39 WIP - initial efforts to restructure the way tuners and tuner

controllers manager sample buffer processing and channel management.
General cleanup across all modules to remove the executor from each
of the start() methods.  Removed the B100 tuner class since it's not
yet implemented.

src/source/mixer/RealMixerSource.java

@@ -17,8 +17,7 @@
  ******************************************************************************/
 package source.mixer;
 
-import channel.heartbeat.Heartbeat;
-import dsp.gain.AutomaticGainControl;
+import source.heartbeat.Heartbeat;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 import sample.Listener;