added RANK and FILE constants
changed the naming of pieces from using numbers to king/queen side
changed OUT_OF_BOARD to DEAD
removed unused variables and dummy()
added piece position
changed ranks direction in actualBoard, now rank 1 is 0 while rank 8 is 7 in the array
removed shadowBoard
changed validateWhite() from Skip to Stop
added moveContinuous() and moveOnce()
added sample assertions
added simple_bishop.csp