Hotfix for segfault if game is not started with default values for rows (6) and columns (7): Default-values of constructor are now 9 for either rows and columns to prevent segfault when creating an instance via assignmentoperator with a desired size other than the default values of 6 & 7 (segfault appeared because the field of the old instance was copied into the new instance which caused a segfault because the old instance had a smaller field than the new one.).