efficient propagation of certainty, two-fold draw scoring, mate display and more.
=1 suitable for training
=2 for play
Currently negabound search depth is one.
Improves play in positions with many certain positions (nrear endgame TBs, mates).
Sees repetitions faster and scores positions more accurately.

…ersion. Increasing threads (e.g. 4 or 6) will get to masters speed now. Further speed fixes (move generator) possible....

…with lto, this yields a speed up by 30-50% in backend=random. In order to fully use CP please use 4 threads+. Changed default temporarily to 4 threads with this commit, to collect more scaling data.

…ds instant play of certain winning moves and avoidance of loosing moves regardless of visits. CP=3 now adds advanced pruning.

- exposed depth parameter (0 is no-look-ahead)
- only two modes CP=1 for training and CP=2 for play
Todo:
- change option from int to choiceoption
- use info.mate to communicate mate scores

- Certainty Propagation is a bool option now, just on or off (default = off).
- Cleanup code and comments
- Threads default = 2, but if certainty propagation is turned on please use 4 threads.

…r certain losses over terminal losses.

fix off by one mate count

…nty-propagation

…nty-propagation

…filtered tb scores if drawn (compatible with new option kSyzygyFastPlayId), comment cleanup.

… updated all syzygy comments. TODO: evalposition parameters

…(struct of gameresult and trigger) as return value.

…' into VidDrome-basic-certainty-propagation