Unregister LUA widgets when the factory is destoyed

Resolves #183

radio/src/gui/colorlcd/widget.cpp

@@ -196,6 +196,12 @@ void registerWidget(const WidgetFactory * factory)
   getRegisteredWidgets().push_back(factory);
 }
 
+void unregisterWidget(const WidgetFactory * factory)
+{
+  TRACE("unregister widget %s", factory->getName());
+  getRegisteredWidgets().remove(factory);
+}
+
 const WidgetFactory * getWidgetFactory(const char * name)
 {
   auto it = getRegisteredWidgets().cbegin();

radio/src/gui/colorlcd/widget.h

@@ -114,6 +114,7 @@ class Widget : public Button
 };
 
 void registerWidget(const WidgetFactory * factory);
+void unregisterWidget(const WidgetFactory * factory);
 
 class WidgetFactory
 {

radio/src/lua/widgets.cpp

@@ -225,6 +225,11 @@ class LuaWidgetFactory: public WidgetFactory
     {
     }
 
+    ~LuaWidgetFactory()
+    {
+      unregisterWidget(this);
+    }
+
     Widget * create(FormGroup * parent, const rect_t & rect, Widget::PersistentData * persistentData, bool init=true) const override
     {
       if (lsWidgets == 0) return 0;