Allow Map Events to change the monster/item counts

Fixes getting an instant 100% kills on Megaboss events before the Megaboss
spawns.
Add a temporary to make the Megaboss event not break stupidly with RLA loaded
Make Map Special Event Chance customizable
Whoops
Fix a bunch of stuff with map events, also XP/Rank reduction on respawn
Merge branch 'master' into newoutpost