Post-jam update

Since the game jam is not over yet, I'm not updating the game's direct download just yet, but you can get the newest version of the game in this post.

Changes:

• The kill rule now applies to sectors in addition to rows, lines
• Killing a number now disable the opponent's ability to place that number for a turn.
• The lines between numbers now update dynamically to show the relationship between the connected numbers
• The main Sudoku grid is no longer walled. 
• A limited undo system is in place though it can be buggy.  Full undo system. Press Z to undo.
• A new globally unique initial grid arrangement is generated daily.
• Eye candy.
• Fix being  able to stack numbers in one place