[PythonCAD] Automatic entity splitting now in PythonCAD

[Wilbert Knol]

> The autosplitting code also cause a few hiccups with the recently
> reworked entity splitting code - I think I've fixed those problems as
> well. Do an 'svn update' to get the changes.

Done. It's working well, here (revision 2305).

As an aside, while playing with the new features, I noticed that pythoncad 
gets a bit confused when I 'select' a segment of a rectangle, and then try to 
delete that segment, or even other segments:

wk at wk:~/pythoncad$ ./gtkpycad.py
Traceback (most recent call last):
  File "/home/wk/pythoncad/PythonCAD/Interface/Gtk/gtkimage.py", line 146, 
inda_general_event
    event, _tool)
  File "/home/wk/pythoncad/PythonCAD/Interface/Gtk/gtkmodify.py", line 353, in 
delete_button_press_cb
    gtkimage.redraw()
  File "/home/wk/pythoncad/PythonCAD/Interface/Gtk/gtkimage.py", line 1085, in 
redraw
    _obj.draw(self, _color)
  File "/home/wk/pythoncad/PythonCAD/Interface/Gtk/gtkinit.py", line 118, in 
_draw_segment
    _coords = self.clipToRegion(_xmin, _ymin, _xmax, _ymax)
  File "/home/wk/pythoncad/PythonCAD/Generic/segment.py", line 410, in 
clipToRegion
    _x1, _y1 = self.__p1.getCoords()
AttributeError: 'NoneType' object has no attribute 'getCoords'
            

Anyway...it's no big deal...I thought I should mention it.

Wilbert.