This widget provides a dynamic image that looks just like a Mac OS 9
progress bar. Packed around it are four Frames, north, south, east and
west, within which you can stuff additional widgets. For example, see how
Tk::Copy::Mac uses several Labels and a CollapsableFrame widget to create a
reasonable facsimile of a Macintosh copy dialog.

The following option/value pairs are supported:

* *-width*

The maximun width of the Progressbar.