Simplified lamp logic by reducing unnecessary brackets, `if` statements, ternary operators and boolean comparisons.
Added new lamps:
- `i-gear1` - 1st gear in the gearbox is active
- `i-gear2` - 2nd gear in the gearbox is active
- `i-hydrolockup` - The gearbox is locking the engine and wheels together
Additionally, fixed motor overload and differential relay lights not turning off when the battery is turned off.
- Add engine_max_temp and engine_is_hot fields to heat_data structure
- Add EngineMaxTemperature field extraction from .fiz files
- Add engine overheat check comparing Ts with engine_max_temp
- Add four new overheat lamp indicators:
- i-oil_overheat
- i-water_overheat
- i-wateraux_overheat
- i-engine_overheat
- Add lamp update logic to turn on/off based on is_hot flags
- Add lamp initialization in clear_cab_controls()
This implements issue #77 - overheat lamps for diesel engines.
The lamps will turn on when:
- Oil temperature exceeds OilMaxTemperature
- Water temperature exceeds WaterMaxTemperature
- Auxiliary water temperature exceeds WaterAuxMaxTemperature
- Engine temperature exceeds EngineMaxTemperature
Each check includes 8-degree hysteresis to prevent rapid on/off cycling.
