Ent's Copper Rails

What is Adds

• Copper Rails - A new rail that sets a minecart's speed limit, in four oxidation tiers (each with a waxed variant).
• Per-cart speed control - every minecart remembers its own top speed, from 8 up to 64 blocks/second.
• Fast without flying off - carts stay glued to the track even at full tilt, so high speed finally feels good.