Update Notes for v1.2.2

[b]Bug fixes[/b] [list] [*] Fixed visual inconsistencies caused by the background of the cells in the game grid overlapping the cell border on some devices [*] Undo should now not work when a level is completed [/list] [b]Improvements[/b] [list] [*] Better performance by only drawing the active cells in the game grid [/list]