Hmm, upgrades

What looks like a simple update this time. Agents (and other movable objects in the world) are now linked to the layer they inhabit, so you can, as in the above gif, hide every floor above ground floor which will also hide the agents when they're in that floor. As they move "downstairs" they become visible. There is a bit of an issue that the top of the stairs is considered by the engine as the 1st floor instead of the ground floor but it'll get there... eventually. For the moment that's more of a feature than a bug.