#2518 P25P1 LSM Decoder enhancements. (#2523)

* Uses same shared architecture and symbol processor pattern as other C4FM decoders.
* Adds soft symbol processing and sync detection.
* Removes RRC filter and replaces with improved channel filter.
* Viterbi soft symbol decoding with demodulator reliability weighting
* Improved sync reacquisition in low SNR
* Improved handling for phase wrapping and interpolation
* NAC Tracker updated to track by NAC count
* Native buffers returning partial buffers
* Message processor uses only valid LDU1 words
* Reduced phantom TDU messages
* Tuner/Channe frequency error corrections don't reset the symbol trackers and fix possible divide by zero error
* LSM timing error detector now updates per symbol block size instead of sample buffer size - faster convergence
* New unit tests
* Resolves several issues, including a lagging sync detect offset issue in the recently updated P25P1 C4FM decoder.
* Consolidate filter designers for each protocol back into the FilterFactory class.
* DMR, P25 Phase 1 C4FM and LSM, and P25 Phase 2 decoders design the baseband filter once and share the taps across the I and Q filters.

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

src/main/java/io/github/dsheirer/dsp/c4fm/C4FMMessageFramer.java

@@ -47,6 +47,20 @@ public abstract class C4FMMessageFramer
         return process(symbol);
     }
 
+    /**
+     * Process the symbol decision along with the soft symbol it was decided from and the soft symbol reliability (ie
+     * inverse of the soft symbol noise variance).  Framers that can weight soft decision decoding override this method.
+     * Default implementation discards the reliability.
+     * @param symbol decision
+     * @param softSymbol equalized soft symbol in radians
+     * @param reliability of the soft symbol
+     * @return true if the framer emits a valid message that includes this symbol.
+     */
+    public boolean process(Dibit symbol, float softSymbol, float reliability)
+    {
+        return process(symbol, softSymbol);
+    }
+
     /**
      * A sync pattern is detected
      */