Adaptive Step Size - Adjust around events

[teubert]

Requirement Text
Adjust 'auto' step size behavior to adjust step size around event occurrence to better capture time of event

Background Information
Right now auto step size adjusts around stop_pts, save_pts, and switching points in Piecewise load estimators. If 'dt', stepsize is too large, this can lead to imprecision in time of event.

Suggested Solution
Reduce dt as you event state approaches 0 in a configurable way

Could also: If state of event is negative, step back by half a step. 2.

DoD

• Implement feature
• Add to example
• Add tests
• update documentation
• Add to change notes for next release