GWEN improvement: allow to navigate TreeControl and ComboBox using the cursor keys

btgui/Gwen/Controls/TreeNode.h

@@ -12,6 +12,14 @@
 #include "Gwen/Controls/Button.h"
 #include "Gwen/Controls/ScrollControl.h"
 
+enum
+{
+	ITERATE_ACTION_OPEN=1,
+	ITERATE_ACTION_CLOSE,
+	ITERATE_ACTION_FIND_SELECTED_INDEX,
+	ITERATE_ACTION_DESELECT_INDEX,
+	ITERATE_ACTION_SELECT,	
+};
 
 namespace Gwen 
 {
@@ -51,6 +59,9 @@ namespace Gwen
 
 				virtual void DeselectAll();
 
+				virtual void iterate(int action, int* curIndex, int* resultIndex);
+				
+
 				Event::Caller	onNamePress;
 				Event::Caller	onSelectChange;
 				Event::Caller	onSelect;