Signals

-Added Chain Signals

-Added a rail replacement interaction, when right-clicking a rail block with a different rail item, it replaces the block in the world.

-Improved cart pathfinding, including less unnecessary detours with red signals in some cases, and better support for tracks like Junction Tracks from RailCraft.

-Signals now only emit redstone to their left to allow for more compact set-ups involving rails on the other sides of the signal.

-Other item interaction mechanics can now access the Cart Hopper to interact with the cart connected (to access the fuel slots, for example).

-Signals now will orient themselves to the rail they are placed next to (unless there are no or multiple rails neighboring).

-Path Signal now spawns particles to indicate the cart that is preventing a green signal.

-API: Added ICartLinker interface to inform Signals about Carts that are connected as a single train.