Add Position output to Grid and Split6 operator

Added a position output to the Grid operator which outputs a number between 1 and the number of buttons on a grid starting at the top left hand side. This should work with all grid sizes but I've only been able to test it with my 64. This is a method that I sue alot in max/msp so its useful to me I thought I'd share it as it may be useful to someone else.

The Split6 operator is just an copied and edited verison of Split4 but with 6 outputs.