added tempo bonus
What is quite original here, is that I implemented the tempo in the search, rather than in the eval. IMO this is way better for several reasons:
- ss->nullChild optimization is possible due to the fact that the eval stays symetric
- all eval dependant stuff in the search is not polluted. for example ss->eval >= beta ensures that we never do double null moves
- tempo is only accounted for when we chose to stand pat with the eval, missing the opportunity to increase our position score by playing a quiet move, for eg.

Starting with a low value, to be on the safe side. I do believe that the value should be smaller and smaller for longer time controls.

4000 games in 5"+0.05"
1143-992-1865 [51.9%] LOS=99.9%

signature = 9148454