[PythonCAD] Lots of stuff just sent to the repo

[Art Haas]

Hi.

The list has been quiet lately, so here is some news. I've just sent a
large number of updates to the public svn repo. The changes improve the
undo/redo abilities of the program considerably, and in the next week or
so I hope to add even more changes that provide another large benefit.

The undo/redo stuff is more robust now after doing some entity deletion
actions. One problem in the thirteenth release involves undoing a
deletion. The recreated entity was reconstructed correctly - mostly -
but the entities all have a unique numerical id, and the new entity had
a different id than that which was deleted. This different value would
mess up further undo or redo actions on that object. The id of recreated
objects is now the same as that of the object it replaces, and this
change means undoing or redoing deletions is more robust. BTW, the id
I'm writing about is not the result of Python's id() function.

My plan is to make a release at the end of the month, as I am focusing
on solely undo/redo improvements right now. There are still numerous
changes I want to implement between now and then, so hopefully things
will progress smoothly for the next few weeks.

Art Haas
-- 
Man once surrendering his reason, has no remaining guard against absurdities
the most monstrous, and like a ship without rudder, is the sport of every wind.

-Thomas Jefferson to James Smith, 1822