reexport ui dependency

plugins/org.yakindu.sct.model.stext.ui/META-INF/MANIFEST.MF

@@ -10,7 +10,7 @@ Require-Bundle: org.yakindu.sct.model.stext;visibility:=reexport,
  org.eclipse.ui.editors;bundle-version="3.5.0",
  org.eclipse.ui.ide;bundle-version="3.5.0",
  org.eclipse.xtext.ui.shared,
- org.eclipse.ui,
+ org.eclipse.ui;visibility:=reexport,
  org.eclipse.xtext.builder,
  org.antlr.runtime,
  org.eclipse.xtext.common.types.ui,