[CHANGES]
- Sanity-checking of ->add_slot names
- Permit "anonymous" slots with sigils but no names; accessed only
via $slotmeta->value
- Warn when $self lexical is shadowed (partly fixes RT132428)
[BUGFIXES]
- Ensure to run GETMAGIC on ->add_slot names
- Removed extranous and undeclared
use Devel::MAT::Dumper
from unit
tests