Improvements to Board::enought_material...()
Improvements to Board::enought_material...()

Simplify the lamdbas and their usage. Also, move the knight count
section earlier, since it is a simpler and faster check.

MarkZH/Genetic_Chess,MarkZH/Genetic_Chess,MarkZH/Genetic_Chess,MarkZH/Genetic_Chess,MarkZH/Genetic_Chess