Damage Multiplier for Surfaces

Originally written by Ishtvan on http://forums.thedarkmod.com/topic/2974

I don't know if we'll end up keeping this way of defining surfaces or if we'll switch to a "surface map" image, but anyway for now, this is how you can have the surface alter the damage done:

When projectiles hit a surface (and later when melee attacks hit a surface, but I don't think it's coded yet), it checks the following variable in the projectile def for what damage to do:

"damage_mult_<surface type name>" "<value>"

Without the "<>" of course. The surface type name must match exactly, all lowercase. It takes the value for that and multiplies it by the base amount of damage done by the projectile. Later we'll randomize damage more, but this is how it works for now.