PNG Stalkers Safe Blackout + Music v3

Changes in v3:
- Auto-spawn is now much rarer.
- After a stalker spawns, the next spawn is randomly scheduled between 10 and 35 minutes later.
- Puppet Marionette and Jester Grin still trigger the uploaded song when they are near/seen.
- All stalkers still vanish within 5 blocks and trigger blackout + scary sounds.

Commands:
/function pngstalksafe:spawn/puppet_marionette
/function pngstalksafe:spawn/jester_grin
/function pngstalksafe:spawn/all
/function pngstalksafe:auto/on
/function pngstalksafe:auto/off
/function pngstalksafe:kill_all
/function pngstalksafe:test_music
/function pngstalksafe:stop_music
