Add test for dual class/factory inheritance.

If it works properly, this would make pylint happy.

Signed-off-by: Raphaël Barrois <raphael.barrois@polytechnique.org>
WIP on docs, again.

Signed-off-by: Raphaël Barrois <raphael.barrois@polytechnique.org>
WIP: Improve a couple of declarations.

Iterator now cycles by default
SubFactory accepts a factory import path as well
Iterator can be provided with a custom getter

Signed-off-by: Raphaël Barrois <raphael.barrois@polytechnique.org>