- Changed tests so that when one test fails, other unrelated ones don't.
- now options are initialized to their "global defaults" values instead
of hard coded values, so we can set a bunch of options on all entities.
- added a way to set custom column names for belongs_to relations.
- implemented a way to delay setup (to have a behaviour somewhat similar
to something non dynamic). This is to be used in conjunction with the
new "setup_all" function.
- made autoload work for belongs_to/has_one/has_many relations. The user
must provide column names in that case. It would be possible (and quite
easy, I think) to guess things based on foreign keys when there is only
one relation of the same type between two entities, but I haven't done
it yet, and don't plan to do it before the release. It doesn't work yet
for HasAndBelongsToMany relationships.