Modification of checker_board.hpp

Have two functions to seeing if a location on the board is containing a
white piece or a red piece.

Also, changed the type of the board state so that the return values can
be used by the evaluation functions of the neural networks.
Modification of minimax.hpp

Have a prototype of the minimax algorithm for the evaluations of the
board states. There is no recursion in the search at this point.
Modification of tests.cpp

Have the test suit running to see the moves of the minimax evaluations.