Resolves #154 - add right-click contextual channel menus for Now Playing table.

Also disables right-click channel activation from the spectral display as a clean-up action.

src/controller/channel/ChannelProcessingManager.java

@@ -90,6 +90,14 @@ public class ChannelProcessingManager implements ChannelEventListener
         return mChannelMetadataModel;
     }
 
+    /**
+     * Channel model
+     */
+    public ChannelModel getChannelModel()
+    {
+        return mChannelModel;
+    }
+
     /**
      * Indicates if a processing chain is constructed for the channel and that
      * the processing chain is currently processing.