[Etoys] [Enhancement] SimpleSliderMorph heigth fix

[Yoshiki Ohshima]

  Karl,

> SimpleSliders had height set to 2 pixels lots of places making them 
> impossible to adjust. This is changeset set the height to 10 pixels in a 
> lot of classes.

  Wow, this really makes me wonder what was the original authors'
intention.  It was impossible to adjust on a regular computer, and not
to mention OLPC.

  This week, we probably won't push any updates due to the Trial-3
code freeze (but if the freeze becomes longer than we expected, we
might make etoys 2.2 stream), but after that I'll push your change.

  Thank you!

-- Yoshiki