surface: Fixed F15's hitbox position to fit to model.

The model have not looked like touching the ground.
Enabled SampledChartSeries to have lower bound as well as upper bound.

To use this feature, pass 5th and 6th parameters to GLWchart.addSeries()
in a Squirrel sciprt for minimum and maximum bounds, respectively.
surface: Experimenting with PID control on Aerial planes.

This commit adds a mechanism to control with integral of aileron signal.
It's not yet optimized, barely better than before.
There are profiling and debugging feature such as GLWchart monitoring
and runtime parameter adjustments via console variables.
surface: Test with rudder stabilizer, which looks good.
surface: Prevent auto pilot from overshooting altitude control.

If lateral distance is high, the AI won't evaluate altitude difference too much.