- fix rare exception when you spam the run button on a single-line program
- other minor cleanup

Added a few new tasks, removed a brutal one.

- so uh i forgot to remove a debug line whoops

- median puzzle fix

yield return solve maybe possibly probably

- actually fix the multiple of 9 puzzle this time
- made enter and backspace less restrictive
huge thanks to magemage for reporting

- fix bug with closest multiple of 9 puzzle
- tp support by exish

fix bug where you were able to remove the top line completely even if there's a question mark

oops

enter key actually works well now
three new puzzles, if you have any ideas feel free to let me know =)