Documentation updates for acquisitions invoices

Updates to acquisitions invoices documentation, including new 2.4
features. Also moves up some 2.1 documentation that is still relevant.

Signed-off-by: Kathy Lussier <klussier@masslnc.org>
don't let function keys lock the MARC editor

lock = put the interface into a state where it prompts with an unsaved data
warning before closing the interface

Signed-off-by: Jason Etheridge <jason@esilibrary.com>

Conflicts:
	Open-ILS/xul/staff_client/server/cat/marcedit.js
	Open-ILS/xul/staff_client/server/cat/marcedit.xul

Signed-off-by: Pasi Kallinen <pasi.kallinen@pttk.fi>
Signed-off-by: Dan Wells <dbw2@calvin.edu>