LPad - Pad and interleave traces

LPad < small.H jump=2 mask= > large.H

Each initial trace is followed by jump zero traces, the same for planes.

from history	integer	n1, n2, n3
from par	integer	jump =2	how much to expand the axes
	filename	mask	selector for known traces (same size as output)
to history	integer	n2 =n2*jump (if n2 > 1), n3 =n3*jump (if n3 > 1)

See also: LPef