Afterimage-like result visualization for comparison.

[YooSunYoung]

From the experience at the JParc, accumulating real-time results was not needed at all since we can simply use a file if we need longer-term results.
It'll be more-likely now that file-writer is significantly faster (after removing geometry from the run-start message).

There was similar requirements though, to visually compare results over-time (or over-sample environment changes).

I made an example how it would look like as a plot:

It'll be useful if users can select which field triggers the update of the plot. (i.e. sample rotation) as well as the possibility to update it simply over time.