Stubby the hexapod extended servo layer

A modified version of the Stubby the hexapod (https://hackaday.io/project/770-Stubby-the-(Teaching)-Hexapod) radial servo layer. This version corrects for hole alignment w/ respect to the other hexagonal layers, and also features thicker walls to accomodate the #6 machine screw hole diameter. Original STLs found at https://hackaday.io/project/770/log/5818-3d-printer-files