Let rock moles actually eat rocks

[copperwater]

Implement lithivoring (for now, only for rock moles).

• you can eat rocks as a lithivorous monster, and valuable gems taste delicious
• The flintstone YAFM should be un-deferred.
• #933: Lithivorous monsters can gain intrinsic speed by eating a dilithium crystal.
• As with metallivores, gems eaten by monster rock moles should often wind up in their stomachs
  • Dilithium should get destroyed if they got speed from it
  • Rocks should always be destroyed, so that they don't eat a few rock piles and the player kills them later to find them toting around a stomach full of 500 rocks.