This module adds a wizard to merge purchase order. A wizard that can be called from tree view of purchase orders. If merge criteria are validate: All lines of all PO are "transferred" to the first one and some information like 'origin' and 'partner_ref' are concatenated. We post a message on the chatter to indicate when the merge operation occurs and what were the PO concerned. The empty PO are "canceled" Merge criteria: * PO are from the same supplier * PO are in state 'draft' * PO have the same #. currency #. picking type #. incoterms #. payment terms #. fiscal position