Consider using time stamps instead of Nominal or Effective Sample Rate to visualize signals

[Yida-Lin]

I compared some files in SigViewer and in Matlab, and see the signals and events in SigViewer are sometimes not exactly accurate.

Using effective sample rate to display events is a temporary fix, but in the long term maybe we should consider using exact time stamps to display signals. That way we also don't need resampling anymore.