consider ordering Reaction components

[isaacsas]

Two Reactions with the same substrates and products and such can hash differently if there is an order difference between them in the species, products, or generated net stoichiometry (with the latter having an order based on Julia's default dict so not really deterministic across versions). This can cause problems with lists of Reactions not being issetequal. We should consider enforcing a partial ordering of states within Reactions or updating the hashing and equality testing to ensure they don't inadvertently depend on such orderings.