Improve RoboScape library somewhat

[gsteinLTU]

libs/roboscape.xml should really use typing on the key inputs. The "encrypt" block's key should be a number, and the "encrypt++" block should use a list. "encrypt" doesn't throw an error when it gets the wrong type like "encrypt++" does, but that may be worse.

It also has "empty?", map, and ternary blocks that have built-in equivalents now, and a weird string comparison block that returns false for short strings. I'm not sure if any of our lessons use these. The "join words"/"list to word/sentence" might also need to be moved somewhere else.