Autofocus 2.0

[AdvancedImagingUTSW]

Possibly improve the autofocus functionality to be a bit more powerful.

Currently, if it does not find an optimum position, it just stops. If the focus exists beyond the range, we will not find it. We could potentially add a feature to expand the sweep if the optimum is not found.

Also, our best focus is either a max (which is subject to noise) or a fit (which is finicky). We could interpolate the response and find the best focus. Can use the derivative of the interpolation fit to see if a clear maximum was found. Would also tell us which direction the focus is improving in.