Added new subchart pictogram image

plugins/org.yakindu.sct.ui.editor/src/org/yakindu/sct/ui/editor/StatechartImages.java

@@ -10,7 +10,7 @@ import org.eclipse.swt.graphics.Image;
  */
 public enum StatechartImages {
 
-	SUB_STATECHART("icons/obj16/submachine-state-16.png"),
+	SUB_STATECHART_PICTOGRAM("icons/obj16/submachine-pictogram-16.png"),
 
 	LOGO("icons/obj16/logo-16.png");
 	

plugins/org.yakindu.sct.ui.editor/src/org/yakindu/sct/ui/editor/pictogram/SubchartPictogram.java

@@ -23,7 +23,7 @@ public class SubchartPictogram extends Pictogram {
 
 	public SubchartPictogram() {
 		super("Open Substatechart in new Editor",
-				StatechartImages.SUB_STATECHART.image(),
+				StatechartImages.SUB_STATECHART_PICTOGRAM.image(),
 				new OpenSubstatechartHandler(),
 				getHandlerExecutionContextValidator());
 	}