GEP 18: * fix bug with gid of citation not updating
        * allow to add new citation from the citedin tab


git-svn-id: svn+ssh://svn.code.sf.net/p/gramps/code/branches/geps/gep-018-evidence-style@22502 4ae1f11a-8b86-4847-b8af-ab372f36d1fd