Resolves #519 (#520)

- Clears stale patch groups
- Reworks the audio playback panel label update code to properly update
  talkgroups and aliases in concert with the audio playback.
- Removes code that was truncating playback aliases at 32 characters.

src/main/java/io/github/dsheirer/identifier/IdentifierCollection.java

@@ -1,7 +1,7 @@
 /*
  * ******************************************************************************
  * sdrtrunk
- * Copyright (C) 2014-2018 Dennis Sheirer
+ * Copyright (C) 2014-2019 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
@@ -84,7 +84,7 @@ public class IdentifierCollection
         return mUpdated;
     }
 
-    protected void setUpdated(boolean updated)
+    public void setUpdated(boolean updated)
     {
         mUpdated = updated;
     }
@@ -114,6 +114,14 @@ public class IdentifierCollection
         return Collections.unmodifiableList(mIdentifiers);
     }
 
+    /**
+     * Indicates if this collection has no identifiers
+     */
+    public boolean isEmpty()
+    {
+        return mIdentifiers.isEmpty();
+    }
+
     /**
      * Get a list of identifiers by identifier class from this collection.
      *

src/main/java/io/github/dsheirer/identifier/MutableIdentifierCollection.java

@@ -22,6 +22,8 @@ package io.github.dsheirer.identifier;
 
 import io.github.dsheirer.identifier.configuration.AliasListConfigurationIdentifier;
 import io.github.dsheirer.sample.Listener;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
 import java.util.Collection;
 import java.util.Iterator;
@@ -32,6 +34,7 @@ import java.util.Iterator;
 public class MutableIdentifierCollection extends IdentifierCollection implements IdentifierUpdateProvider,
     Listener<IdentifierUpdateNotification>
 {
+    private final static Logger mLog = LoggerFactory.getLogger(MutableIdentifierCollection.class);
     private Listener<IdentifierUpdateNotification> mListener;
 
     public MutableIdentifierCollection()