Tevo adjustable end stop

I designed an adjustable endstop for the tevo to be compatible with the ninjacookie dual Z brackets, as there was no option for those who have mechanical end stops.

Some notes:

- it's not perfect. I have 2 screw holes for mounting to the base extrustion but only one will work becuase the t nuts interfere when trying to mount with both screws (still works fine)

- Use a m4 screw, T nut, and washer on the x carriage extrusion to contact the switch (see picture)

- Its very close to the