#39 WIP - adds support for timestamped complex buffers so that decoded

messages and events can be accurately timestamped, and more importantly,
allocated traffic channels can request to be pre-loaded with buffered
samples to ensure that traffic channels don't miss any samples that
are currently missed due processing latency inherent in current buffer
sizing.  This should reduce the clipping of starting messages or voice
on the traffic channels.

Restructures processing path for tuner frequency and sample rate change
events.  The tuner now embeds these events in the sequence of buffers
that are generated immediately after the event occurs since those are
the buffers that will be impacted by the change.  Previously, the change
event would be broadcast throughout the system and would impact any
buffered/cached buffers.  This also reduces the number of source event
change listeners that have to be managed.  Note: this change is not yet
implemented in all tuners ... only in the TestTuner implementation.

Updates the polyphase channelizer to now buffer channel results and then
dispatch the buffer to the channel output processors to improve efficiency
of using float arrays versus single value complex float processing.

src/main/java/io/github/dsheirer/source/tuner/TunerController.java

@@ -197,12 +197,13 @@ public abstract class TunerController implements Tunable, ISourceEventProcessor,
     }
 
     /**
-     * Usable half bandwidth - total bandwidth minus unusable space at either end of the spectrum, minus the blocked
-     * center bandwidth.
+     * Usable half bandwidth - total bandwidth minus unusable space at either end of the spectrum.
+     *
+     * Note: this does not account for any DC spike protected frequency region at the center of the tuner
      */
     public int getUsableHalfBandwidth()
     {
-        return (int)(getUsableBandwidth() / 2) - mMiddleUnusableHalfBandwidth;
+        return (int)(getUsableBandwidth() / 2);
     }
 
     /**