Wanhao Di3 Y Carriage Plate

A remix of Steamkraft's Wanhao Duplicator I3 Y-Plate.

Changes made:
- Added a 3-point leveling location to the side since a front/back location doesn't quite work (the screw would either hit the Y stepper motor or the front plate- you'll need to rotate the build plate 90 degrees and extend the wires for 3-point leveling). I left the original hole for a potential cable chain mount.
- Added extra bearing and belt bracket mount holes. This allows use of 3 bearings or 4 bearings, and to or