Altair 4.0.0

This is the fourth version of Altair. Altair now supports Fischer Random Chess (Chess 960) by toggling the UCI option.

Compared to previous releases, this release is not as major, and this is due to the release primarily marking the final version of Altair using an internal mailbox-based board representation. Due to the mailbox-based board representation, Altair is comparatively slow and has much more potential utilizing bitboards.

Altair is now at an estimated 3080 Elo, and almost all the patches since v3.0.0 have been search or time management related.

Self-play LTC test:

ELO   | 85.41 +- 13.46 (95%)
CONF  | 40.0+0.40s Threads=1 Hash=128MB
GAMES | N: 1000 W: 320 L: 79 D: 601

Thanks to @archishou for a speed-up patch, and thanks to everyone in this OB testing instance for contributing invaluable resources that have enabled me to improve Altair.