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/airspy/AirspyTunerConfiguration.java

@@ -0,0 +1,119 @@
+/*******************************************************************************
+ *     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 source.tuner.airspy;
+
+import javax.xml.bind.annotation.XmlAttribute;
+
+import source.tuner.TunerConfiguration;
+import source.tuner.TunerType;
+
+public class AirspyTunerConfiguration extends TunerConfiguration
+{
+	private int mSampleRate = AirspyTunerController.DEFAULT_SAMPLE_RATE.getRate();
+	private int mIFGain = AirspyTunerController.IF_GAIN_DEFAULT;
+	private int mMixerGain = AirspyTunerController.MIXER_GAIN_DEFAULT;
+	private int mLNAGain = AirspyTunerController.LNA_GAIN_DEFAULT;
+	
+	private boolean mMixerAGC = false;
+	private boolean mLNAAGC = false;
+
+	/**
+	 * Default constructor for JAXB
+	 */
+	public AirspyTunerConfiguration()
+	{
+		this( "Default" );
+	}
+	
+	public AirspyTunerConfiguration( String name )
+	{
+		super( name );
+	}
+	
+	@Override
+    public TunerType getTunerType()
+    {
+	    return TunerType.AIRSPY_R820T;
+    }
+
+	@XmlAttribute( name = "sample_rate" )
+	public int getSampleRate()
+	{
+		return mSampleRate;
+	}
+	
+	public void setSampleRate( int sampleRate )
+	{
+		mSampleRate = sampleRate;
+	}
+	
+	@XmlAttribute( name = "if_gain" )
+	public int getIFGain()
+	{
+		return mIFGain;
+	}
+	
+	public void setIFGain( int gain )
+	{
+		mIFGain = gain;
+	}
+	
+	@XmlAttribute( name = "mixer_gain" )
+	public int getMixerGain()
+	{
+		return mMixerGain;
+	}
+	
+	public void setMixerGain( int gain )
+	{
+		mMixerGain = gain;
+	}
+
+	@XmlAttribute( name = "lna_gain" )
+	public int getLNAGain()
+	{
+		return mLNAGain;
+	}
+	
+	public void setLNAGain( int gain )
+	{
+		mLNAGain = gain;
+	}
+
+	@XmlAttribute( name = "mixer_agc" )
+	public boolean isMixerAGC()
+	{
+		return mMixerAGC;
+	}
+	
+	public void setMixerAGC( boolean enabled )
+	{
+		mMixerAGC = enabled;
+	}
+
+	@XmlAttribute( name = "lna_agc" )
+	public boolean isLNAAGC()
+	{
+		return mLNAAGC;
+	}
+	
+	public void setLNAAGC( boolean enabled )
+	{
+		mLNAAGC = enabled;
+	}
+}