The feature in question is described in bug 2952; to
summarize the enhancement, which the earlier patch
description did not do, the list of bibs in an
import record batch now includes a column linking
each import record to the bib that was actually created
or updated when the import batch was committed.

The improvements in this patch are:

* If bib in import batch has not been committed, it
  has not been linked to a matching new or updated bib.
  In that case, do not create a link to a guaranteed
  404 (/cgi-bin/koha/catalogue/detail.pl?biblionumber=)

* When reverting an import batch, set matched_biblionumber
  to NULL for affected records - otherwise, the Bib
  column will include links to bibs that may no longer
  exist.

* Fixed a minor HTML validation error.

Signed-off-by: Galen Charlton <galen.charlton@liblime.com>