Add tooltips to a few things

[LordMonoxide]

• [x] Hammer - used on ores to get nuggets
• [x] Clay oven - place on furnace
• [x] Clay crucible - place on furnace
• [x] Unhardened clay things - place by firepit or furnace
• [x] Hardened cast - right click on crucible
• [x] Mattock - right click to till/strip
• [x] Furnace - attach to fire pit