Adds airspy USB tuner support and updates the spectral display

component.

-Airspy supported with 10 and 2.5 MSps sample rates.  Additional
decimation may be added later.

-Spectral display updated to include smoothing and filtering options.

Note: the decimated output of a tuner channel from the airspy is
48,076.9 samples per second, versus the normal 48 kHz decimated rate.
This is 1.0015 times the normal rate and doesn't appear to impact the
decoders or audio processing.  Therefore, no fractional resampling has
been added.

src/source/tuner/TunerChannelSource.java

@@ -1,6 +1,6 @@
 /*******************************************************************************
  *     SDR Trunk 
- *     Copyright (C) 2014 Dennis Sheirer
+ *     Copyright (C) 2014,2015 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
@@ -28,6 +28,7 @@ import java.util.concurrent.atomic.AtomicBoolean;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
+import sample.Buffer;
 import sample.Listener;
 import sample.complex.Complex;
 import sample.complex.ComplexBuffer;
@@ -36,12 +37,12 @@ import source.SourceException;
 import source.tuner.frequency.FrequencyChangeEvent;
 import source.tuner.frequency.FrequencyChangeEvent.Attribute;
 import source.tuner.frequency.FrequencyChangeListener;
-import util.Oscillator;
 import controller.ThreadPoolManager;
 import controller.ThreadPoolManager.ThreadType;
 import dsp.filter.FilterFactory;
 import dsp.filter.Window.WindowType;
 import dsp.filter.cic.ComplexPrimeCICDecimate;
+import dsp.mixer.Oscillator;
 
 public class TunerChannelSource extends ComplexSource
 							 implements FrequencyChangeListener,
@@ -292,7 +293,7 @@ public class TunerChannelSource extends ComplexSource
 					{
 						mBuffer.drainTo( sampleBuffers, 4 );
 				
-						for( ComplexBuffer buffer: sampleBuffers )
+						for( Buffer buffer: sampleBuffers )
 						{
 							/* Check to see if we've been shutdown */
 							if( mDispose.get() )