Bump version 2.1.0 -> 2.1.1

Bump 2.0.1 -> 2.1.0

Bump version 2.0.0 -> 2.0.1

Bench: 861138 nodes 2327400 nps 370 ms

Tune speculative pruning margins

Based on ~115k games with the auto tuner. Causes _massive_ pruning
compared to original values. Apparently this is still better than the
inevtibale misses that this induces in the search.

Tune speculative pruning margins

Based on ~115k games with the auto tuner. Causes _massive_ pruning
compared to original values. Apparently this is still better than the
inevtibale misses that this induces in the search.

Reduce history stats impact

Some very light tuning against the starting position, where this seems
to be the optimal multiple of ten in terms of number of nodes visited
when doing a depth 9 search.

Add history heuristic

Use all information when sorting root moves

We only stored the found value when it improved alpha. But regardless of
whether or not it improves alpha, we should keep track of the value so that
when we re-sort the root moves for the next depth, we have all the moves in
the best known ordering.

Add internal iterative deepening

Add futilty, razoring and delta pruning