[Etoys] Performance improvements form 3.9 (backported) #3

[Yoshiki Ohshima]

  Marcus,

  I forgot to mention, but 

> Change Set:		SubMorphCopy-md
> Date:			16 October 2006
> Author:			Marcus Denker

  This one was considered "it seems to be ok.  We don't find any code
that changes the result".  I don't remember the further discussion,
but was there some analysis, or it is just seems to be ok as it is
long time in 3.9 line images?

  Also, we've changed the MorphExtension a bit, I put a subsequent fix
for it.

  Thank you!

-- Yoshiki