#2494 P25P1 and NXDN Decoder Enhancements. (#2514)

- Updates P25P1 C4FM decoder to use same pattern developed for NXDN.
- Both share the C4FM symbol processor and equalizer.
- P25P1 updated with Garner style timing error detector
- NXDN filters updated to use a combined RRC and inverse sync filter all in one.
- P25P1 replaces RRC with band limiting filter
- P25P1 enhanced with dynamic PLL balance updates to combat multi-path fading, in addition to the sync detection training window.
- Decoder PPM error reports now only sent after 2x consecutive sync detections to prevent tuner PPM corrections from noisy/isolated false sync detects.
- Soft error correction added to both P25P1 and IDEN.

Co-authored-by: denny <dennis.sheirer@gmail.com>

src/main/java/io/github/dsheirer/gui/viewer/sync/FMSyncVisualizer.java

@@ -50,7 +50,7 @@ public class FMSyncVisualizer extends VBox implements ISyncResultsListener
     private final XYChart.Series<Number, Number> mSymbolSeriesMarker = new XYChart.Series<>();
     private final ScatterChart<Number, Number> mConstellationChart = new ScatterChart<>(mConstellationI, mConstellationQ);
     private final XYChart.Series<Number, Number> mConstellationSymbols = new XYChart.Series<>();
-    private static final int CONSTELLATION_SYMBOL_COUNT = 50;
+    private static final int CONSTELLATION_SYMBOL_COUNT = 24;
     private int mConstellationSymbolPointer = 0;
 
     private final LineChart<Number, Number> mSampleChart = new LineChart<>(mSampleTiming, mSamplePhase);