Angled MK3 Heatbed Cover with Nylon Filament Hole

I made a few small amendments to the already great design by MIKEYMCC for my MK3.

• Added a support hole for the 3mm Nylon Filament included with my kit to keep the wires in shape
• Reduced the top piece height by a little more than 1mm to make it more low profile
• Moved the Nut pockets to the bottom half so its easier to install and remove NOTE: This only works for the original MK3 SOLDERED bed terminals. The screw terminals on the newer beds will not fit.