[weld-dev] Modularity

I was talking to Ales and Lincoln on IRC about how Weld handles modular environments. Whilst we have a full structure for representing module visibility relationships, we don't have any way of expressing that a bean is private to a module - all beans are exported. I don't think this really is consistent with how modular systems work, and so I think we need to add this to the BDA contract e.g. public Collection<String> getPrivateBeanClasses(); I would suggest returning private/hidden classes rather than public ones here, as it means non-modular envs don't need to adjust their code much to have everything work as normal.