fixed loading presets when dragging them onto existing instrument-track-window (finally closes #2025902)

git-svn-id: https://lmms.svn.sf.net/svnroot/lmms/trunk/lmms@1459 0778d3d1-df1d-0410-868b-ea421aaaa00d

include/instrument_track.h

@@ -50,6 +50,7 @@ class instrumentTrackWindow;
 class instrumentMidiIOView;
 class lcdSpinBox;
 class midiPortMenu;
+class multimediaProject;
 class notePlayHandle;
 class pluginView;
 class presetPreviewPlayHandle;
@@ -153,6 +154,9 @@ public:
 
 	virtual QString displayName( void ) const;
 
+	// simple helper for removing midiport-XML-node when loading presets
+	static void removeMidiPortNode( multimediaProject & _mmp );
+
 
 signals:
 	void instrumentChanged( void );