Add an experimental sync capability

[stvdwtt]

Before we do data assimilation, it would be helpful to re-sync with the experiment in case the layer time is slightly off the simulated layer time.

This could be accomplished by sending the time stamped experimental data with a known offset from some scan path event (e.g. the end of printing for a layer). Then we can modify the scan path between the sync time and the assimilation time so that the simulation reaches the assimilation time correctly (e.g. by modifying the dwell time). This depends on #223.