Fabcore - direct version (L3k)

this a direct extrusion version (can also be used with bowden with a larger printing area than the original) (request by Olivier)
it was design to be used with a L3k extruder : http://www.thingiverse.com/thing:512338

it is same as Fabcore original for x and y axis
z axis is redesign and is more symmetrical
i create a pdf guide to help people build this version
thanks