Sudoku

In the demos\extra\Sudoku there is a Sodoku resolver, as far as I concern it resolves most of the puzzles, there are a few exceptions, but at least it helps my dad once he gets pissed off with a difficult one.

This is one of the currently unsolvable ones

The reason behind is that is defined with many bifurcations (I think), so the resolver once it gets to a dead end, it must rollback and start again in the previous bifurcation, the more bifurcations, the more difficult is for the engine, I hope one day I can revisit this project.