This PR does a couple things at the same time (yeah, sorry about that, but as always, I start working on something and then end up with a stack of small changes ).
Initially I wanted to move the Wooden Horse out of the leg slot to the devices, but I didn't want to break people's inventories, so I added a way to perform inventory fixups on login, allowing items to be moved easily from one group to another. It's a bit of a one-shot, so I don't know how people feel about that, and can take it out if it's not deemed useful. There's also some removed special-cases for some items, since RemoveAtLogin performs the same function.
The meat of the PR changes the Horse to use the "KneelingSpread" pose, removes all of its assets, and updates the rest of the leg assets with a new prerequisite that needs the ability to close legs (via the pose system), superseding "ToeTied" which kinda did the same thing but with an hardcoded list of items.
