changed visibility of view ids. added perspective package export … (#1656)

* changed visibility of view ids. added perspective package export to MANIFEST. related to #1646

* reverted removal of static imports of sct view ids.

* avoiding possibility of name collisions in static imports.

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

@@ -33,6 +33,7 @@ Import-Package: org.eclipse.emf.edit.ui.provider,
  org.eclipse.ui.dialogs,
  org.yakindu.sct.model.sgraph.provider
 Export-Package: org.yakindu.sct.simulation.ui,
+ org.yakindu.sct.simulation.ui.perspective,
  org.yakindu.sct.simulation.ui.preferences,
  org.yakindu.sct.simulation.ui.view,
  org.yakindu.sct.simulation.ui.view.decorator