Reviewed code : Added new classes, fixed bugs, fixed TODOS

-Added enumerated type PositionState for Actions
-Added a BoatCellCoordinates class to get rid of the boolean table
touchedCase
-Added constant for the grid size
-Created a 2D table for actions to avoid potential errors
-Removed unnecessary temporary variables
-Removed some methods on the index of the touchedCase array
-Improved the Play() loop, which now allows only the current player to
play