Improved bst_scoap3_importer

* Better message reporting and sleeping points.

* Match also against DOIs
BibFormat: fix unreferenced variable
BibFormat: refactoring of bfe_INSPIRE_Conferences_other_conf
BibFormat: bfe_INSPIRE_links and pdf/a

* Whitelist also PDF/A files so that they are displayed
  in the fulltext area.
BibFormat: stricter input data in ref correction form

* Makes sure record_id is an integer in the references correction form.