2X Extruder Upgrade for Raffle Alu-Dual Cooling Block (Remix)

This is a small change based on the fantastic work of both rmcniff (http://www.thingiverse.com/thing:222667) and countspatula (http://www.thingiverse.com/thing:256754).
Like countspatula I also recently installed my Carl Raffle Cooling block and hot end upgrade (http://shop.raffle.ch/). As the new cooling block has the hot ends positioned along the center line of the cooling block, a offset of around 3mm is required. The common approach is to add spacers between stepper and cooling block to ge