Introduced promotion to knight, simplified assert
Stronger test condition.
Promotion to knight implemented.
Reduced duplication between knowledge of notations and piece types.
Introduced rook. Promotion to it works fine.
Introduced bishop. Promotion to it works fine.
Reinsurance test for promotion with capture.
Commented queens move
String Constants replaced by usage of the enumeration/notation. Thus duplication is removed.
Introduced immutability test to ensure Position.move is really keeping current position untouched.
Merge pull request #50 from lrozenblyum/PawnMovement

Pawn movement - all promotions