if two doors touch, they are assumed to be connected and operate as a unit.
TOGGLE causes the door to wait in both the start and end states for a trigger event.
START_OPEN causes the door to move to its destination when spawned, and operate in reverse. It is used to temporarily or permanently close off an area when triggered (not usefull for touch or takedamage doors).
Key doors are allways wait -1.
"message" is printed when the door is touched if it is a trigger door and it hasn't been fired yet
"angle" determines the opening direction
"targetname" if set, no touch field will be spawned and a remote button or trigger field activates the door.
"health" if set, door must be shot open
"speed" movement speed (100 default)
"wait" wait before returning (3 default, -1 = never return)