Patch for deleting tiles when commands are deleted from the undo stack

[Cyrille Berger]

On Saturday 20 March 2010, Boudewijn Rempt wrote:
> On Friday 19 March 2010, Boudewijn Rempt wrote:
> > Sure!
> 
> It seems to work now -- I haven't got new regressions indeed.
I actually noticed some problem with undoing with disappearing tiles.

-- 
Cyrille Berger