Resolves issue #23.

Adds audio output display and management options supporting mono and 
stereo output options.

Provides audio output supporting prioritization by talkgroup and/or 
channel selection.

Supports muting all channels, or muting individual channels and
individual audio gain/volume controls.

src/audio/AudioChannelsPanel.java

@@ -0,0 +1,37 @@
+package audio;
+
+import java.awt.Color;
+import java.util.List;
+
+import javax.swing.JPanel;
+
+import net.miginfocom.swing.MigLayout;
+import settings.SettingsManager;
+import audio.output.AudioOutput;
+
+public class AudioChannelsPanel extends JPanel
+{
+	private static final long serialVersionUID = 1L;
+
+	public AudioChannelsPanel( SettingsManager settingsManager, 
+							   IAudioController controller )
+	{
+		setLayout( new MigLayout( "insets 0 0 0 0", "[grow,fill]", "[]0[]") );
+		
+		setBackground( Color.BLACK );
+
+		List<AudioOutput> outputs = controller.getAudioOutputs();
+		
+		for( AudioOutput audioOutput: controller.getAudioOutputs() )
+		{
+			add( new AudioChannelPanel( settingsManager, audioOutput ), "wrap" );
+		}
+
+		/* Add an empty channel panel so that the panel is sized appropriately
+		 * for either a single channel or two channels */
+		if( outputs.size() == 1 )
+		{
+			add( new AudioChannelPanel( settingsManager, null ), "wrap" );
+		}
+	}
+}