Validate tossups heard

[jonahgreenthal]

• [ ] Game TUH should be nonnegative (except in the case of a forfeit)
• [ ] Each player TUH should be ≤ game TUH. 0 could be permitted*, but probably doesn't mean anything, so it should at least incur a strong warning. Negative should never be permitted.
• [ ] Each player TUH should add up to ≥ (powers + tossups + interrupts)
• [ ] Player TUH on each side should add up to ≤ (players per team at a time) * (game TUH)

*For instance, in formats with lightning rounds, a player might be subbed in for the lightning rounds and subbed backed out after.

[jonahgreenthal]

Duplicate of #24, now that I wrote that all out