More metaclass compatibility handling.

More metaclass compatibility handling.

When creating a new class, fix its metaclass compatibility as well as
when extends is called. This means that classes created via
Moose::Util::MetaRole (aka new metaclasses) have their metaclass
compatibility fixed. Sounds crazy, but it basically lets combine
modules which give the caller a new metaclass (like Fey::ORM::Table)
and modules which then apply roles to the caller's metaclass (like
MX::ClassAttribute).

And hey, there's tests.