Prusa i3 Rework - Y-motor Reverse edition with 608 bearing

Motor moved to the back instead of inside the Y-assembly
The belt now rides on the 608 bearing and clears the M10 nut. Allows better fixing to the M10 threaded rod compared to the old version.
Improved upon http://www.thingiverse.com/thing:647115.
Increases Y freedom by approx. 44mm.

The Y-idler Reverse edition adds approx. another 35mm.
http://www.thingiverse.com/thing:646518