Passing a widget instead of an flist with a root widget opens the option of
creating a browser frame that is only part of a window. Passing a full file
name instead of pieces assumed to come from a .py file opens the possibility
of browsing python files that do not end in .py.
The original module-level class and method browser became a module
browser, with the addition of module-level functions, years ago.
Nested classes and functions were added yesterday. For back-
compatibility, the virtual event <<open-class-browser>>, which
appears on the Keys tab of the Settings dialog, is not changed.
Patch by Cheryl Sabella.
Cheryl Sabella
Terry Jan Reedy