Implement uses of souls for orcs

[pjf]

Souls in the rebalance are consumable components. Only the 'great' souls' are useful, and they can only be obtained on the field of battle.

• [x] Tag each of the great enemy souls (dwarf, human, drow, elf) with an appropriate reaction class. (REACTION_CLASS:GREATER_SOUL)
• [x] Souls with that reaction class can be turned into spirit talismans (replaces existing spirit talisman system)
• [x] Particular talismans can be used in meditation to provide building unlocks. Elf souls for the tree-singer, etc.
• [x] Spirit gems (existing item) should be crafted from souls

[pjf]

And tested! Closing with joy. :)