1. Added a box mark to the selected grid 2. Added bouns score when continuously triggering tetris: [list] [*] When triggering tetris consecutively in a short period of time, the second trigger will add 4 extra points (total 1+4+4=9 points) [*] If there is a row increase within the time (both auto-increment or penalty increase), the additional score is deducted until it is 0 [/list] 3. Fix a bug that no miss score will not be recorded on the leaderboard when the game ends without a miss