Prevent PO activation when lineitems have 0 copies

[Bill Erickson]

From the commits:

By default, prevent activation of POs when any lineitems are present that have no copies attached. This adds a new option in the PO UI called "Allow activation with zero-copy lineitems", which will allow the activation to continue even when zero-copy lineitems exist. [It has been suggested that there may be use cases for this, like standing orders].

When PO activation fails as a result of zero-copy lineitems, show the IDs of the zero-copy lineitems along with the failure message.

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working => collab/berick/acq-po-prevent-activate-sans-copies

http://git.evergreen-ils.org/?p=working/Evergreen.git;a=shortlog;h=refs/heads/collab/berick/acq-po-prevent-activate-sans-copies

[Mike Rylander (mrylander)]

Picked to master ... great justice and all that. Thanks!