Visual debugging tool

[Wikunia]

I would like to add a generic debugging tool to this which saves the tree nodes in a json file as this is extremely helpful in my ConstraintSolver project. This project would simply need to create this JSON struct and I need to refine and publish my Javascript visual branch and bound debgugger then :wink:

The "interface" can be seen here: https://opensourc.es/blog/constraint-solver-bugs-and-benchmarks/#the_real_bug

[matbesancon]

you can also require from the local solver to implement a print_to_file function which prints the most adapted format (or pass an extension)