Added pen support to EditorControls.

Right now, editor controls dont work with pen pointer because `event.pointerType === "pen"` is ignored. This patch fixes it.

editor/js/EditorControls.js

@@ -121,6 +121,7 @@ function EditorControls( object, domElement ) {
 		switch ( event.pointerType ) {
 
 			case 'mouse':
+			case 'pen':
 				onMouseDown( event );
 				break;
 
@@ -140,6 +141,7 @@ function EditorControls( object, domElement ) {
 		switch ( event.pointerType ) {
 
 			case 'mouse':
+			case 'pen':
 				onMouseMove( event );
 				break;
 
@@ -154,6 +156,7 @@ function EditorControls( object, domElement ) {
 		switch ( event.pointerType ) {
 
 			case 'mouse':
+			case 'pen':
 				onMouseUp();
 				break;