Navigator should use a different icon while panning

The Navigator uses the same hand icon regardless whether panning
the red square or not, this branch tries to fix that, #4738
Includes a cleanup of icon names, i.e. the crosshair should not be
called the hand.

rtgui/edit.h

@@ -717,7 +717,7 @@ inline EditDataProvider* EditSubscriber::getEditProvider () {
 }
 
 inline CursorShape EditSubscriber::getCursor (const int objectID) {
-    return CSOpenHand;
+    return CSHandOpen;
 }
 
 inline bool EditSubscriber::mouseOver (const int modifierKey) {