Joystick-config: fix ToggleButton, add AP-DISC

Fix the created binding for toggle buttons.

Add autopilotDisconnect helper to controls.nas, and expose the new
function in the joystick configurator dialog. 

Fixes from Henning Stahlke

Nasal/controls.nas

@@ -558,6 +558,13 @@ var applyApplicableBrakes = func(v, which = 0)  {
     }
 }
 
+var autopilotDisconnect = func() {
+    var aps = props.getNode("/controls/autoflight").getChildren("autopilot");
+    foreach (var ap; aps) {
+        ap.getChild("engage").setBoolValue(0);
+    }
+}
+
 # 1: Deploy, -1: Release
 var deployChute = func(v) setprop("/controls/flight/drag-chute", v);
 

Nasal/joystick.nas

@@ -418,7 +418,7 @@ var PropertyToggleButton = {
 
     var c = prop.getNode("binding", 1).getNode("command", 1).getValue();
     var p = prop.getNode("binding", 1).getNode("property", 1).getValue();
-    return ((c == "property-toggle") and (p == me.prop));
+    return ((c == "property-toggle") and (p == me.binding));
   },
 
   getBinding: func(button) {
@@ -566,6 +566,7 @@ var buttonBindings = [
   NasalHoldButton.new("Brakes (air/wheel)", "controls.applyApplicableBrakes(1);", "controls.applyApplicableBrakes(0);"),
   NasalHoldButton.new("Parking brakes", "controls.parkingBrakeToggle(0);", "controls.parkingBrakeToggle(1);"),
   NasalHoldButton.new("NWS toggle", "controls.toggleNWS(0);", "controls.toggleNWS(1);"),
+  NasalButton.new("Autopilot disconnect", "controls.autopilotDisconnect();",0),
 
   PropertyToggleButton.new("Total Freeze", "/sim/freeze/clock"),
 

gui/dialogs/button-config.xml

@@ -486,6 +486,19 @@ var assignButton = func(cmd) {
       </binding>
     </button>
 
+    <button>
+      <row>10</row>
+      <col>3</col>
+      <halign>fill</halign>
+      <legend>Autopilot disconnect</legend>
+      <binding>
+        <command>nasal</command>
+        <script>
+          assignButton("Autopilot disconnect");
+        </script>
+      </binding>
+    </button>
+
     <text>
       <row>0</row>
       <col>4</col>