Thrust bearing base for MeArm V0.4

To address slop issues in the MeArm base, here is a new base for the MeArm V0.4 utilizing a 65mm O.D. x 45mm I.D. x 5mm thrust bearing. I ordered one from ebay for 4 dollars. This base replaces the original square one attached to the top of the (4) M3 x 20mm bolts.

Also included is a dxf file that has been cleaned up (The original v0.4 dxf uses splines instead of lines and arcs. Ugh!) and re-nested to fit on an 8 1/2" x 11" sheet for us American folk. No other changes were made. It is versio