Effects Update 1

This PR hopes to reestablish some of the basic moddability of effects that my old health PR attempted to accomplish before becoming bogged down.

However I currently seem to be getting some random seg faults, can anyone help to spot the cause? Stacktraces are proving fairly inconclusive on my end, just spouting out long strings of alphanumeric characters and ???'s.
Out of curiosity: why are there two body parts used here? One is used for the environmental protection check and the other is the actual effected body part. Why should it be possible for example to attack the left leg and (if it succeeds) infect the right arm?