Bowden extruder mount for RigidBot on filament rack

This is a merge of Bowden extruder mount for RigidBot and Rigidbot spool holderm adapted for mounting on back ( http://www.thingiverse.com/thing:1306535 ).

Since I have an enclosure for the rigidbot I have no space on the frame to position it, so I added it to the filament holder, it actually positions the extruder in a comfortable location.