Support for changing the "turtle" with cursor-command. 

I've been teaching the basics of programming to my 4 year old daughter and 5 year old son with turtle roy. They seem to enjoy it, but I though I'd add some spice to it with the "turtle" images :). I added some png images to the images-dir. The cursor command takes the name (without .png suffix) as the only parameter.

Next I'm going to add some "fairy dust" and "road dust" animations which can be turned on and off like the pen.

Kiitos loistavasta softasta!