Also, add Skellam as an HIRM distribution.
Also (and this is actually the majority of this change), call init_theta when creating a non-conjugate distribution. init_theta needs a random number generator, so a bunch of relation and irm methods now need to take one of those when they didn't before.
Also, add Skellam as an HIRM distribution. Also (and this is actually the majority of this change), call init_theta when creating a non-conjugate distribution. init_theta needs a random number generator, so a bunch of relation and irm methods now need to take one of those when they didn't before.