(total_work): New parameter maxpop. Callers changed.
(newe, prod): Use total_work(). Old code failed to limit military
workers, thus didn't match the update.
(do_feed): Simplify.
This is safe, because the only caller passed a copy of the latter
created with getvec(), and populace() doesn't change it.
(tax): Replace getvec() by direct, read-only item access.