Dual E3D Extruder for RepRapPro Mendel

I liked the simple design of the OB1.4 Dual E3D extruder from downeym, so I remixed it to fit on the RepRapPro Mendel carriage.
It replaces the complete front nozzel mount of the carriage, so its easy to swap it with the original.
I placed also two holes in the mounting cap to mount a 50mm fan.

##Update:
I have updated the design for better airflow through the cold end to the sides and not so much to the hot end.
There is now also a possibility to mount PLA fan ducts on the side.