actor icons prevent channel connectors to align straight
Reported by Edward Lee:
The Kepler icons seem to be sized so that Vergil's snap-to-grid
doesn't really work. If I connect an output port to a relation
to an input port, I can't get the connections to give me straight
lines. This is rather unfortunate, as it makes all Kepler diagrams
look a bit sloppy. This can be fixed by resizing the Kepler icons
to match the default size in the basic Vergil editor for Ptolemy II.