Fixes issue #3401 by adding a "SpeciesCanConsume" helper proc

SpeciesCanConsume() specifies whether a mob has the racial ability to eat and drink.  It's checked in the "canconsume" reagent proc (called when someone is fed or tries to eat/drink).  Humans, aliens, and monkeys can all be fed food and drink as a result, and service borgs can no longer drink their own coolaid (to get diseases or otherwise).