Angular Acq Search: Perl API changes

Angular Acq Search: Perl API changes

* Add __age (interval), __starts, and __ends operators.

Update __between to support __castdate modifier, for a more natural
comparison of dates entered by humans to timestamps stored in the
database.

* teach open-ils.acq.lineitem.retrieve more fleshing

In particular, teach it how to flesh the LI provider,
Vandelay queue, and claim policy so that Angular LI search
can display them without having to make additional server
requests.

* Add additonal fleshing for purchase order, selection lists,
  and invoice searches.

* Add au_by_id option

This specifies performing queries on au-linked fields by
ID rather than adding joins to query the fields by user
barcode or username, etc.

* Implement "contains" operator for provider searches.

This is similar to how user searches are handled.

This patch contains work by Mike Rylander, Galen Charlton, and Jason
Etheridge.

Signed-off-by: Mike Rylander <mrylander@gmail.com>
Signed-off-by: Jason Etheridge <jason@EquinoxInitiative.org>
Signed-off-by: Galen Charlton <gmc@equinoxinitiative.org>