reoder.hlp: ins $reoder, MCR>reo ...		'reoder' is re-order

Will reoder fields in a record, for each record of a file.
Can insert constant text, drop/duplicate fields, justify.
Each output record is built from 1 input record by appending fields.
Each field is derived (as a function of whole input record) from a sfn.

MCR>REO <stdin >stdout [-wsfc] sf1 sf2 ... sfn
-w (default) warn about search failures
-s be silent about search failures
-f (default) search failures are fatal
-c continue after a search failure
sfn	a 'select field' command: enclose in '' or "" if it has space(s)
	constant:	Sn	leading n spaces
			Tn	trailing n spaces
			\...`	text constant ...
	select-field:	<begin>|<end>
		where <begin> & <end> are both pointer movers
pointer movers: a concatenation of these is a legal <begin> or <end>
<mover> is {CL} Justify {CL}
CL	constant or locator
locator	An	pointer is put so that n chars of record are to its left
	+n	add n to pointer
	-n	subtract n from pointer
	`text`	pointer is scanned until text is seen
	~text`	pointer is scanned until anything but text is seen
	>	search to right (pointer left to right of target)
	<	search to left (pointer left to left of target)
Justify	Ln	left justify, making field n columns
	Rn	right
	Cn	centre
