New collections

[aroberge]

I should aim to have at least a couple examples for each of the following world collections:

• Reeborg intro (done)
• Reeborg intro extra (supplementary examples)
• SK CS 20 (done)
• Variable, function arguments, etc. (includes list index and math operations)
• Dot notation (list methods, etc.) and using Reeborg with other robots present ??
• OOP - creating new robot classes
• recursive puzzle (similar to lightbot and robozzle)
• turtle
• graphics
• string exercises
• Advanced programming ??
• Demos (showing world creation technique with no task to solve)