apply setup or ignore next trigger method

[carandraug]

The spectra plot redraws itself when the live setup changes. If a setup is applied, this triggers up to 5 changes, for the dye, source, detector, and each of the paths. I don't think this is what's causing slowdown but would sure be nice to not have so extra triggers.

[carandraug]

There were actually a few more change events. For example, before replacing the filters in the path, emptying it would trigger a change event. And if the new setup had the same dye, a change event would also be triggered.

Reduced the number of change events triggered in 4e533aa by catching early on when a change would not actually change a component.

In the context of filters, I think the setters for a Setup paths, should be doing the registering to event listening so that we could replace a path in the Setup.

Would still be nice to define all components of a setup triggering only one change event but this change already cuts it down a lot.