Make humanization more granular

[fs-c]

Let the user specify an offset interval for a number of kps ranges, for example

<10 kps -> [-10, 10]ms
<20 kps -> [-10, 20]ms
<30 kps -> [-30, 40]ms
<40 kps -> [-100, 100]ms

(Explanation: If kps is between 0 and 10, add an offset between -10 and 10, if kps is between 10 and 20...)

For every hitpoint, determine the kps at that point in time and generate a (uniform?) random number in the corresponding interval. Add the result to the hitpoint time.

Integrating this cleanly into the UI will likely require a new GUI solution.