Adds one command that hurts entities with arbitrary damage, of the form;
/hurt <entity> <amount>
entity - can be of the standard forms you would use with /kill (i.e. @p, @e[type=minecraft:chiken]).
amount - the amount of damage to apply to the entity, as a float (i.e 1.73, 0.4, 2).
currently the damage type is generic but, im working on adding a third optional parameter for damage type.
