Eternal Minecart

There is a little flakiness with the eternal rider. As it is an entity and not a player, it can't randomize on  it's own. so it randomizes and uses values from the closest player and due to the latency sometimes he doesn't obey the turning rules of "go mainly north" or  one of the other candles.

Also, i stopped short of adding up and down for the cart. not because i didnt code it and get it to kinda work, but because minecraft itself is inconsistent with loading structures. the same code would work one time and not work the next. i can probably work around this if there is enough interest in this add-on, but for now i'll just leave it as a neat toy that only does n-s-e-w