Always update avatar graphics when changing equipment (even artifacts)

Fixes #1213

Some artifacts can determine which items can be equipped (e.g. Owl
Figurine lets us equip Mage gear with a base Mental of 1). We need to
update the player graphics when removing such artifacts to reflect the
removal of dependent gear.
Merge pull request #1214 from dorkster/artifact_refresh

Always update avatar graphics when changing equipment (even artifacts)