Add ActionContainer::addSeparator(...)

Gets rid of a lot of code duplication.

Change-Id: I2ce38fb38a0b61cb821e0bdc7bcc9a7ccdf9da72
Reviewed-by: hjk <qthjk@ovi.com>

src/plugins/cmakeprojectmanager/cmakeprojectconstants.h

@@ -50,9 +50,6 @@ const char CMAKEPROJECT_ID[] = "CMakeProjectManager.CMakeProject";
 // Menu
 const char M_CONTEXT[] = "CMakeEditor.ContextMenu";
 
-// Actions
-const char SEPARATOR[]        = "CMakeEditor.Separator";
-
 } // namespace Constants
 } // namespace CMakeProjectManager