Have CAD be a separate toggle (set cad on/off)

examples/simple_repeater/MyMesh.h

@@ -150,6 +150,9 @@ protected:
   int getInterferenceThreshold() const override {
     return _prefs.interference_threshold;
   }
+  bool getCADEnabled() const override {
+    return _prefs.cad_enabled;
+  }
   int getAGCResetInterval() const override {
     return ((int)_prefs.agc_reset_interval) * 4000;   // milliseconds
   }