Too many vertices in ImDrawList

[fenix31415]

First, thank you for this awesome project!

The problem is that I want to deal with many vertices. This is why I get the following assertion error.

As the comment suggests, it is a good idea to skip drawing nodes that are outside of the editor view.

I am not quite familiar with DearImgui, in particular with this project -- I just started using it. But I think that it is possible to skip calls here: before update, it can check whether a node inside the render window and draw it only if it is in inside.

If this edit does not breaks imgui/ImNodeFlow architecture/invariants, I even can try to implement it myself and create a PR.

Thank you!