Big Einsy for MMU - lesser vent holes and honeycomb in the back wall

Removed non-mandatory ventilation holes at the top and bottom. In the back wall honeycomb holes inserted instead of slots. 

Cover with fan is recommended. I have used one of these with fan mount: Big Einsy Case Cover Honey Comb remix with Prusa's logos 

Take the cable covers from here: https://www.printables.com/model/31558-big-einsy-case/files