OpenSCAD Alternate Mendel X Axis Motor Bracket (Q45042)

When I tried to print the original version that rhys-jones made, Skeinforge choked on the *very* high element count in that model. Turns out all of the rounds and holes are meshed *really* fine. So all I did here was recreate it in OpenSCAD. This had the benefit of reducing the polygon count for the holes (sort of as described by nophead here: http://www.thingiverse.com/thing:6118) I tried to make the scad file the same geometry as the previous version, but OpenSCAD doesn't like me to make tangent cuts for the big rounded cutout, so I removed the rounds and left it square. Shouldn't change the assembly at all.