Resample only the visible traces

[jvdd]

Only resample the traces that are shown, and do not resample the not shown (i.e., toggled off) traces.

This is not straightforward, as toggling a trace in the legend does not result in a callback event (i.e., pure front-end event).
To fix this, we should pass the visibility state of the front-end via the trace-updater. Needs some more thought..

[jayceslesar]

I might be able to take this on within the next two weeks