Prusa Extruder Carrage

I edited the carriage from here: http://www.thingiverse.com/thing:135353
To support Linear bushings that are in an aluminum casing.

UPDATE: Version 2.
Better hole placement, with some slack.
Removed unnecessary plastic wall for the belt holder. (the linear bearing housing pushes against the belt either way)
added holes for belt tensioning mechanism.

UPDATE: Version 3.
Made the bottom longer, to have the ability to stick a led strip section.
Added holes around to be able to zip tie ca