ANET A8 PLUS Z Endstop fine adjustment

First of all, the original design is ingenious! Thank you ibschreiber!

Assembly instructions:
- Mount the switch holder to the frame, add the switch
- put a M3x35 or similar through the legs hole
- add the foot to the screw, tighten it a little bit, not too much or you'll deform the bottom surface. You can glue the screw into the foot to give it a better hold.

Calibration:
just turn the screw using the six sided foot, enjoy!

Note:
A good calibrated printer is essential for the sc