GEP 18: fixes with citedintab. 
 *show unused citations also
 *correct switching between citation by updating citation displaytabs
 *backref, correct handling of connectid


git-svn-id: svn+ssh://svn.code.sf.net/p/gramps/code/branches/geps/gep-018-evidence-style@22496 4ae1f11a-8b86-4847-b8af-ab372f36d1fd