Purging and Archiving

	If you never purge or archive, your system will continue to work as usual.
	However over time the current P/O file will increase in size, causing
	searching and reports to take longer, having to parse thru older information.

	Archiving and purging provide a way of putting completed stuff into the history
	files, and keeping only later P/Os in the current files.

	Archive means COPY completed P/Os to the P/O History file.
	The source P/Os remain in the Current file.
	
	Purge means Remove a P/O and its line items. In Greux, the system
	will not purge a P/O, UNLESS it is already in the History file, ie
	has been archived.
	
	Read the help files for each operation for more information.