Size() factors position of analog and digital bar relative to icon.
Create display unit for potions. Track using potionId.
Fix display issue on items. Also align text proepryl for left/center/right horizontal justification.
Tweak Potion defaults. Analog only, beneath Icon.
Generalise hiderules to not depend on DisplayStats
Add hiderules to DisplayPotion. Default hide when empty.
Fix bug in analog bar not scaling properly.