This converts AVG commands to wireframes. We don't try to track
color or intensity. (This is a disassembler, not a graphics
converter; perfection is not required.) The various rotation and
animation options are still enabled, though they're not terribly
useful for this.
Commands that are meant to be used in series, such as font glyphs,
tend to use (0,0) as their left edge and baseline. This puts the
shape in the upper-right corner of the thumbnail, which makes
everything smaller. The change adds a "re-center" option to the
wireframe renderer that computes the visible bounds and adjusts
the coordinates so that the center of the object is at (0,0) for
display.
