Bug 17317: ILSDI: Getavailability method with id_type=bib implementation

Bug 17317: ILSDI: Getavailability method with id_type=bib implementation

To test this patch you should try to send a query to you opac formatted
this way :
http://[your-opac-domain-name]/cgi-bin/koha/ilsdi.pl?service=GetAvailability&id=[biblionumber]&id_type=bib

You should get availability status for all the items of the matched
bibliographic record.

Signed-off-by: Hector Castro <hector.hecaxmmx@gmail.com>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>
Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>