Initial commit of redesigned internal processing and audio management.

Note: Several of the decoders are currently non-functioning in this
commit.  If you want the latest functioning codebase, please checkout
the commit prior to this one.  All decoders will eventually be updated
with this new architecture.

Currently broken:
- Logging and recording
- Aux decoders (Fleetsync/MDC/LoJack/Tait)
- LTR/Passport decoders

Changes in this commit:
- Module architecture for decoders and components with central
provisioning by the DecoderFactory
- Transition from Complex sample stream processing to float buffer
processing for improved memory management
- Redesigned filter structures - to support buffers and streams
- Resolved several memory leak issues
- Universal sharing of the thread pool manager
- Added centralized audio management with call/user prioritization and
new gui with mute/volume controls
- Embedded audio metadata for eventual streaming support
- Redesigned ProcessingChain to support independent re-use
- Added new TrafficChannelManager to handle traffic channel allocations
- Traffic Channel pool size and Call timeout available in P25 and
MPT1327 configs
- Redesigned channel and decoder gui components

src/audio/squelch/SquelchController.java

@@ -0,0 +1,122 @@
+/*******************************************************************************
+ *     SDR Trunk 
+ *     Copyright (C) 2015 Dennis Sheirer
+ * 
+ *     This program is free software: you can redistribute it and/or modify
+ *     it under the terms of the GNU General Public License as published by
+ *     the Free Software Foundation, either version 3 of the License, or
+ *     (at your option) any later version.
+ * 
+ *     This program is distributed in the hope that it will be useful,
+ *     but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *     GNU General Public License for more details.
+ * 
+ *     You should have received a copy of the GNU General Public License
+ *     along with this program.  If not, see <http://www.gnu.org/licenses/>
+ ******************************************************************************/
+
+package audio.squelch;
+
+import sample.Broadcaster;
+import sample.Listener;
+import sample.real.RealBuffer;
+import sample.real.RealSampleListener;
+import sample.real.RealToRealBufferAssembler;
+
+/**
+ * Squelch control - receives single audio samples or real audio buffers and
+ * adjusts squelch state either based on the audio samples or based on external
+ * control inputs.  
+ * 
+ * Assembles received single audio samples into real sample buffers for 
+ * consumption by an external audio processor, like the AudioPacketProcessor
+ * class.
+ */
+public abstract class SquelchController 
+				implements Listener<RealBuffer>, RealSampleListener
+{
+	private Broadcaster<SquelchState> mSquelchStateBroadcaster = new Broadcaster<>();
+	private Listener<RealBuffer> mAudioListener;
+	protected SquelchState mSquelchState = SquelchState.UNSQUELCH;
+	protected SquelchMode mSquelchMode = SquelchMode.MANUAL;
+	
+	private RealToRealBufferAssembler mSampleAssembler = new RealToRealBufferAssembler( 512 );
+	
+	public SquelchController()
+	{
+		mSampleAssembler.setListener( this );
+	}
+	
+	@Override
+	public void receive( float sample )
+	{
+		mSampleAssembler.receive( sample );
+	}
+
+	@Override
+	public void receive( RealBuffer buffer )
+	{
+		if( mAudioListener != null )
+		{
+			mAudioListener.receive( buffer );
+		}
+	}
+
+	public abstract void setSquelchMode( SquelchMode mode );
+
+	public SquelchMode getSquelchMode()
+	{
+		return mSquelchMode;
+	}
+
+	public void setSquelchState( SquelchState state )
+	{
+		mSquelchState = state;
+	}
+
+	public SquelchState getSquelchState()
+	{
+		return mSquelchState;
+	}
+
+	public boolean isSquelched()
+	{
+		switch( mSquelchMode )
+		{
+			case AUTOMATIC:
+			case MANUAL:
+				return mSquelchState == SquelchState.SQUELCH;
+			case NONE:
+				return false;
+			default:
+				return false;
+		}
+	}
+	
+	public void addSquelchStateListener( Listener<SquelchState> listener )
+	{
+		if( listener != null )
+		{
+			mSquelchStateBroadcaster.addListener( listener );
+			
+			/* Send current squelch state to the listener */
+			listener.receive( mSquelchState );
+		}
+	}
+
+	public void removeSquelchStateListener( Listener<SquelchState> listener )
+	{
+		mSquelchStateBroadcaster.removeListener( listener );
+	}
+	
+	public void setAudioListener( Listener<RealBuffer> listener )
+	{
+		mAudioListener = listener;
+	}
+	
+	public void removeAudioListener( Listener<RealBuffer> listener )
+	{
+		mAudioListener = null;
+	}
+}