More fixes... the game may be beatable now.

- Added comments for broken shit
- Fix score.ans generation
- Handle invalid @if <x> is <y> then do constructs the same as original
- Handle incorrect @do <x> is random <y> <z> constructs the same
- Fix @if <x> is/=/equals <y> variable args (length, etc)
- Lower-case argument to @routine
- Handle @itemexit properly
- Use draw_box() for popup_menu()