Bug 9665: add RIS and BIBTEXT bibliographic record export to staff interface

Bug 9665: add RIS and BIBTEXT bibliographic record export to staff interface

The OPAC offers RIS and BIBTEX as choices for bibliographic downloads,
but the staff client was missing these options. This patch adds them.

To test, view a record in the staff client (detail.pl, MARCdetail.pl,
etc.) and click the "Save..." toolbar button. BIBTEX and RIS should be
available and functional.

Signed-off-by: David Cook <dcook@prosentient.com.au>
Signed-off-by: Chris Cormack <chrisc@catalyst.net.nz>
Signed-off-by: Galen Charlton <gmc@esilibrary.com>