GUI app with nim

[Vindaar]

Fair enough. Both things can be added of course. The amount of work strongly 
depends on what functionality you actually need though. And for the interactive 
plots what kind of performance you expect; something as basic as matplotlib's 
interactive interface should be almost trivial and can be done by just 
redrawing the whole plot on each interaction. If you'd need to interactively 
view O(1e6) points or the like that's a different matter.