Health bar now clamps to [0, 100] and combines body + engine health, so it actually reaches 0 when the vehicle is destroyed (#2).
Aircraft and boats no longer get the ground-vehicle HUD or speed limiter. Fixes the Hydra being capped to ~22 km/h and prevents the HUD from showing while flying (#5, #15).
The seatbelt key prompt is now driven by Config['seatbeltLabel'] and pushed to the NUI via a new setLabels event on vehicle entry. Rebinding the seatbelt key no longer requires editing index.html (#8).