Implement member name qualifications

[TheJJ]

These are already described in the specification, but not implemented yet. They are necessary when an object inherits from multiple parents and name conflicts occur.

The name qualifications can explicitly designate which object the referenced member is linked to. That means we can't just store the member name in an object, but instead store a tuple of (originating_object, member_name) as the member identifier. The originating_object is resolved at load time to the object that initially defined the member.