[Localization] turtleart-activity.po

[Markus Schlager]

Hi Chris,

Some time ago I already mentioned the strange behavior of some 
Etoys-po-files where translations of certain strings get lost when 
updating the po-files from the templates. This ist still an issue.

Now I'm encountering the same problem when updating fructose 0.84: string 
68 "set heading" looses its translation and get's marked fuzzy with a 
wrong translation "seth"  (instead of "setze Richtung").

Markus