Conveyor Belt directions

Progress! You can now (sort of) specify which direction a belt should go, by holding down the button and pushing the stick in the four cardinal directions, then letting go.

The animations are all in there, and the positioning's mostly right, but we'll see about that once there's more than one type of item.

The conveyors still pass from left to right though, despite the visuals, and the UI/highlighting is still hot garbage :D (I have plans to radically simplify it though)