Message 225194 - Python tracker

This patch does two things

1. Refactor pyshell-breakpoint-refactor.diff to reflect changes in pyshell-breakpoint-refactor.diff

As in pyshell-breakpoint-refactor.diff, the set/clear(_here) breakpoint methods are refactored into logical methods.

2. If the filename is not set, text.bell() is replaced with a dialog to prompt the user to save the file.