Based on a change from Paul Blankenbaker, make the "show" attribute for

Based on a change from Paul Blankenbaker, make the "show" attribute for
a field an empty string if the field is zero-length; for some reason,
the existing code doesn't handle that correctly.

Also, the NetPDL Visualization Extension:

	http://www.nbee.org/Docs/NetPDL/NetPDLVisualization.htm

seems to imply that "value" has to be present, so display it even if the
field is zero-length.

svn path=/trunk/; revision=19862