More Functionality for Minecart Furnaces

A few ideas for improving Minecart Furnaces :

- It has the GUI of a regular furnace. The more you smelt, the longer it will travel until the furnace is done smelting. Add in Blast Furnace and Smoker Minecarts to complement this

- Minecart Furnaces can take items from Minecart Chests and output them, letting the Minecarts travel for even longer (and have automated smelting)

- Using chains on various minecarts will link them together

Minecart Chest ---chain--- Minecart Furnace ---chain--- Minecart Chest
Elaborating : Because the Minecart Furnace is chained to 2 Minecart Chests, the Minecart Furnace can be toggled to take and output items to either the Minecart Chest in front or behind it.