P25 LSM decoder work in progress. Adds a CQPSK decoder based on Max's (KA1RBI) scope.py and gardner loop.

The CQPSK decoder is starting to take shape, but needs more tweaking and testing.  It's not keeping a good lock on strong P25 signals.  I have to add some more features to the intrumentation package to allow me to visualize the internals of the CQPSK decoder so that I can get a better sense of what needs fine tuning.

The CQPSK decoder may work for anyone that wants to sync the repo and run the build script.

src/controller/Editor.java

@@ -20,6 +20,7 @@ package controller;
 import javax.swing.JPanel;
 
 import net.miginfocom.swing.MigLayout;
+import controller.channel.ChannelValidationException;
 
 public abstract class Editor extends JPanel
 {
@@ -33,4 +34,18 @@ public abstract class Editor extends JPanel
     public abstract void save();
     
     public abstract void reset();
+
+    /**
+     * Override this method to allow the editor to inspect the argument for
+     * valid configuration
+     * 
+     * @param editor - any editor
+     * 
+     * @throws ChannelValidationException if the configuration is not compatible
+     * with this editor's configuration.  Supplies a validation text value for
+     * display to the user 
+     */
+    public void validate( Editor editor ) throws ChannelValidationException
+    {
+    }
 }