BibFormat: HDREF reformats referenced recIDs
BibFormat: HDREF reformats referenced recIDs

* HDREF is special in the sense that records referenced by
  the records being reformatted also need to be reformatted.
  (closes #998)

inveniosoftware/invenio-formatter,tiborsimko/invenio-formatter,inveniosoftware/invenio-formatter,inveniosoftware/invenio-formatter,tiborsimko/invenio-formatter,tiborsimko/invenio-formatter