change random event antag spawns to be based on dead players instead of dead antags

[Mouse]

Benefits include, but are not limited to:

1.  General chaos.  The worse it gets, the worse it gets.
2.  Gets people back in the game, since apparently player population is super important or something.
3.  Provides an additional complication to murderhobos and antag teamups, which tend to annoy a pretty significant portion of the playerbase.  I mean sure, you can go and wipe the entire station as wizards in under 20 minutes, but if suddenly wolves and wraiths and blobs are spawning in things are gonna get a bit nastier for you.
4.  Comedy.

Downsides include, but are not limited to:

1.  Stuff.
2.  Things.