XL Advanced Delta Printer Calibration

This is an extra large version of the Advanced Delta Printer Calibration part by dolpin (http://www.thingiverse.com/thing:745523). Full credit goes to dolpin for the original design, and the associated explanation. Please see his part for associated templates and procedure.

I remixed the part so that I could calibrate my Openbeam Kossel XL more accurately - this part fills the print bed up to nearer the edge, so you get a better idea of the printer performance near the edge of the bed, which