ControllerConnectionDialog: improved auto detect feature for controllers

When opening up the ControllerConnectionDialog by default auto detect
is enabled and all MIDI input devices are selected. Upon the first
event all devices but the one the event came from get unchecked. This
eases the process of assigning MIDI controls to software controls.
(cherry picked from commit 27f5d20e05)

include/MidiPortMenu.h

@@ -43,9 +43,12 @@ public:
 	virtual ~MidiPortMenu();
 
 
+public slots:
+	void updateMenu();
+
+
 protected slots:
 	void activatedPort( QAction * _item );
-	void updatePorts();
 
 
 private: