Beirut Chess

[alexobviously]

https://en.wikipedia.org/wiki/Beirut_chess

This is a nice one because it depends on a few features that are all things I want to implement in the near future.

• Secrets (Variants with secrets #32)
• Perspective output (Rules that modify player perspectives (e.g. fog of war) #30)
• Custom move types
• Variant-specific move formatting (Variant-specific move formatting #46)