* Added boss enable linedef (type 449).

	- Frontside x offset = boss ID (determined via parameter for all bosses)
	- Noclimb flag = disable mode
	- Bosses don't do a fuckin' THING - no state updates, no player searches, no sounds, no lua, no nothin' - and it's all totally netsynced.
	- The only thing they WILL do is flash infinitely if you hurt them, but this is designed for stuff where you're not meant to be in the same room as the boss til it's activated.
	- All bosses of all IDs are automatically enabled on mapload, then if an enable mode version of this linedef is present in the map for a specific boss id, that boss id is automatically disabled.
* Add multi-boss support via parameter for:
	- All bosses' MT_BOSSFLYPOINT search
	- Boss 5's waypoint search
	- Oldbrak's waypoint search (this one's for you, jood)