Customizable Replicator Dual 5mm Drive Blocks

This is a revised drive block derived from http://www.thingiverse.com/thing:53125
I used OpenSCAD to mirror the STL files after I resaved them from Meshlab. They wouldn't load correctly before. I changed the size of the bearing axle to accomodate a 5x10x4mm bearing that is easily available from any hobby shop that carries 1/10th scale cars. I made the pivot screw hole slightly larger, and shaved off the top of the lever to fit in the replicator 1. There are mirrored versions for the left extruder as well.