History length slider

[Krazy0]

The max history length slider has a dead zone on the right. Minor issue.

[pleroy]

There is always a "dead zone" but in most sliders it's invisible. Because the slider is exponential, if you only move it a bit, it would want to increase the history length by a few seconds or even milliseconds. Since the history length has a granularity of 1 min, this has no effect.

For the other sliders (the ones that control burn) the granularity is much smaller (e.g., 0.001 m/s) so in practice any movement of the slider has an effect.

I am changing the progressivity of the history length slider to reduce the dead zone. It won't go away entirely, though.