Per Sal's request (slightly modified):

* Do not allow any joining spectators if anybody got onto the last lap while not in FREE PLAY (this is the same condition as nospectategrief, for consistency).
* Reset nospectategrief to 0 if there is literally nobody playing, to prevent a fully locked-out server.
* This means it's not a problem to reset spectatorreentry even with the map command.
* Change the default for spectatorreentry to 30 seconds, from 60.