Refining statistics information

This step is the base block to understand how much any
further optimization can impact on performance
Performance improvement: solutions's space reduction

Constraints admitting only one solution reduce the solution's
space of other cells (on the same row, column and/or dial)
Tests on the default case shows 15% less iterations
Iterating optimize loop and tentavi optiBoard

Optimize is a loop, that stops when no change are introduced
- an optimizaion could activate futher optimization, then a loop is
   needed

The board is adopting a "smarter" cell order. Find out it the new order
is effectively smarter