force at least 3 head roles to be occupied during a rev round

[babayetu83]

yes, the idea was to balance it since there's 3 head revs there should at least be 3 heads. it would also be too obvious if say it were all heads were to be filled for there to be a rev round. or maybe the whole system could be rejiggered so that it nudges more people into head roles more often. still way to easy to win a rev round since sec is usually a ghost town and you'll often have an army of revs to kill a single person before anyone knows what's going on