Name with_container_arithmetic flags consistently #279

I always have a hard time remembering which options correspond to the decorated container being the outer/inner structure. Might consider (at some point, doesn't have to be here) renaming so that everything is referenced in relation to the container, e.g., number_bcasts_across, bcasts_across_obj_array, container_types_bcast_across?

Originally posted by @majosm in #190 (comment)