Reformat the set and map ops so that they the same as the riak_dt ones.

According to Russell's recent changes,

* Sets have add_all and remove_all (to distinguish single adds/removes
  from lists of them).
* Sets also have {update, ListOfOps} for applying multiple
  adds/removes in one go.
* Maps have {update, ListOfOps} where the list includes add, remove,
  and a field-specific update. (Really, this is unchanged from
  before.)