[entity api] unify set_attributes / set_relations into a cw_set method. Closes #2423719 Allowing similar usage as create_entity/cw_instantiate. Update cw code base to remove deprecated calls.

[workflow ui] fix state/transition edition form on existing entity. Closes #2423531 It should not return unrelated entities only in case where the entity exists. Also fix a deprecation warning, vocabulary values should be an unicode string.

[predicates] fix predicates that erroneously evaluate the entity passed as a parameter as a boolean, instead of testing its existence in the keyword arguments -using the kwargs.get('entity') idiom instead of 'entity' in kwargs or similar- ; closes #2424288