[Feature] A more capable skipper

**Context**
I am drawing a special kind of oscilloscope that is synchronized with the phase of my FM synthesizer.
While it make sense for me to draw lines between points that are near in phase; when my oscillator resets to zero it does not make sense to draw a line. Here is a screenshot with the offending lines:

**Feature description**
I want to control which line segments should be skipped with a generic callback, like in ```ImPlot::PlotLineG```. I believe this is the most flexible approach. I could also add a flag but the behaviour would be very specific to my usecase.
I believe I have the bandwith and the skill to make a pull request, but I would like your opinion on the way to do this because I don't want to lose time on a design that would be rejected. For example, should I also implement this feature for other types of plots ?

I believe making yet another RendererLineXXX class is the way to go ?
Edit: I made a PR with my design: #699