Update Board class, implement rotateRight() method.
Update Board class, implement rotateTop() method.
- Update Board class, implement rotateDown() method.
- Update Test class, add testRotateRight() method to test rotateRight() method in Board class.
- Update Test class, add testRotateTop() method to test rotateTop() method in Board class.
- Update Test class, add testRotateDown() method to test rotateDown() method in Board class.
Update Board class, add leftMerge() method to handle merging cells in case of left rotation.
 Update Main class, add call to leftMerge() method on board object.
Update Board class, add rightMerge() method to handle merging cells in case of right rotation.
Update Main class, add call to rightMerge() method on board object.
- Update Board class, add topMerge() method to handle merging cells in case of top rotation.
- Update Main class, add call to topMerge() method on board object.
- Update Board class, add downMerge() method to handle merging cells in case of down rotation.
- Update Main class, add call to downMerge() method on board object.
Update Board class, increment USER_SCORE variable in case of merge
 Update Main class, display user score when game over.
 Update Test class, add testLeftMerge() method to test leftMerge() method in Board class.
Update Test class, add testRightMerge() method to test rightMerge() method in Board class.
Update Test class, add testTopMerge() method to test topMerge() method in Board class.
Update Test class, add testDownMerge() method to test downMerge() method in Board class.