Modified locking system for MK5 extruder

I had some problems with the original MK5. My hot end was moving during filament retraction.

I made a new locking system using two M3x10 bolts.
I also had to modify the body.
If you have problems during slicing, try with the latest version of Slic3r (1.0.0.2 RC2).

I will add two holes to maintain accessories in the next version.


Apologies for the english translation, I'm french...