- Added events.
--- Random events can now happen after the third stage. (5% chance of happening, if not overriden)
--- Currently there are two events in the gamemode:
----- Antlions: Antlions unborrow from the ground.
----- Scanner Canister: Modified City Scanners arrive on the map, that scan any player they see. If a player is scanned, a Headcrab Canister is launched at them.

- Added cvars:
--- fof_event_chance_of_happening | Changes the chance of an event happening. (0 means events are disabled)
--- fof_event_antlion_enabled | Enables the Antlion Event
--- fof_event_scanner_enabled | Enables the Scanner Canister Event