Coasters: Engineered

Added

• Magnetic launch track. Apply fin plates to a coaster curve to accelerate passing carts like a real linear synchronous motor.
• Force-based physics. Thrust goes through the physics engine, so heavier trains accelerate more slowly and the force appears in the force diagram overlay.
• Launch runs. Connected launch curves share one speed and direction, set from a value box on any anchorpoint and energized with redstone.
• Launch hum, magnet field particles, status lamps, Ponder scenes, and a server-synced config for thrust, acceleration and speed limits.