there must be a specialization of traits::point_type to define the underlying point type (even if it does not consist of points, it should define this type, to indicate the points it can work with)
there must be a specialization of traits::indexed_access, per index (min_corner, max_corner) and per dimension, with two functions:
get to get a coordinate value
set to set a coordinate value (this one is not checked for ConstBox)