Trivia plugin: fix crash in timer mode (again)

This whole time I thought negative values were falsey. At least I caught it before it could crash anything again.
Also fix /triviarank picking up the wrong alt's rank
Merge pull request #1364 from Morfent/trivia

Trivia plugin: fix crash in timer mode (again)
Merge remote-tracking branch 'upstream/master'
Merge branch 'master' of https://github.com/awolffromspace/PC-Battle-Server
Updates