Minor Inventory update + rules cleanup

I've updated the Cairn inventory (again), probably for the last time.

Party Inventory is gone. All PCs start with a torch, rations & a backpack that can be cleared out and used as a sleeping bag. 
I've added carts, horses & mules which can increase slot counts, though typically with some downside. 

Otherwise, I simply cleaned up the formatting and removed inconsistencies. A few tables got new entries, but those are a surprise.