contest form: rollback last change/ alternate way of handling mandatory seats
cleanup: fix indentation in contest.php
contest form: protect multiple SQL statements with transactions
contest form: automatically include rows for missing seats

This way, when 'Update' is clicked, the seats will get created.
contest form: do not try to alphabetize participants
contest form: use default game if available
contest form: use seat icons when available
contest form: make columns list a little more customizable
contest form: implement 'clear_row' btn