Pow 38 - Parasite ~complete

Not fully bug-tested.  Right now Parasite and Symbiote will both add the
Symbiote power to the squirrel that jump onto--this allows for
breakaway.  I don't know, though, if squirrels are ending up getting
this power uninentionally.  TODO: deal with that.
Pow 39 and 40 Complete

Not extensively bug-test cause I be tireeeed.