Nav's Motors Inc. — 0.2.1

• No more stutter when you get in a vehicle — the driver's dashboard was being redrawn dozens of times per frame on big modpacks, dropping the framerate from ~100 to 18 FPS; now it draws once.
• Stutter report — if the game hitches, /navdiaglocal start records a performance report to logs/navmotors-diag-*.txt so we can look into it (off by default; you can also have it record automatically whenever you board a vehicle, in the config).