CAT-69 Volume merge bug

CAT-69 Volume merge bug

Create function in update_items to handle
find_or_create_volume api call.

Create helper function to match acns and get
the amount of copies in supplied volume in PO.

Create helper function to get number copies from
current volume.

Clean up gather_copies().

Remove instances of direct attempts at modifying
IDL properties, replace with the proper method
calls.

Add helper function to set the acn for the items in the
current PO.

Add FM_ACN_RETRIEVE.authoritative call to find_or_create
helper function.

Set temp_acn's label class, prefix, and suffix
to their object's id within g.find_or_create_volume().

Remove unnecessary loop from g.render_batch_button()

Fix incorrect iteration style to
array-friendly one.

Signed-off-by: Kyle Huckins <khuckins@catalystdevworks.com>
 Changes to be committed:
	modified:   Open-ILS/xul/staff_client/server/cat/update_items.js