Comment fixes, code layout, and refactor of warning generation code

Comment and code layout speak for itself.

The no-toilet and no-staffroom warning code both have 2 if conditions when to give warnings, of the form

    if self.world.day == N and not self.is_{toilet,staffroom} and <other conditions> then ..

I refactored this check out into a surrounding if, and eliminated the self.is_X variable.

The no-toilet code also lost a "self.year == 1" condition, as the if may also trigger for years > 1 (the statement executed is the same in both cases).