Just a minor refactor along the planned option change. This commit will
make it easier to update (i.e. copy) the VO options without copying
_all_ options. For now, behavior should be equivalent, though.
(The VO options were put into a separate struct quite early - when all
global variables were removed from the source code. It wasn't clear
whether the separate struct would have any actual purpose, but it seems
it will now. Awesome, huh.)