* Got entirely rid of path.py.

* Many modules: fixes for new, stricter, argument passing rules
  (most changes were automatic ones -- not all of this is tested!).
* gwin.py: now uses mainloop.py for its main loop and window admin.
* mainloop.py: always call dispatch() with event as a tuple!
* Fix bug in pdb's 'clear' command -- don't set the bpt but clear it!