Compact Wade's extruder and X Carriage.

This is not the extruder you're looking for. If you're looking for the extruder referenced in Josef Prusa's i3 design, see http://www.thingiverse.com/thing:24219

After installing http://www.thingiverse.com/thing:12538 , with the extruder tangential to the x-axis, I found that I had caused quite a problem with the Z axis - the drive motor would collide with the printer's frame when Z > 30, and X < 10.

So, it was back to the drawing board - same goals as last time:

1) It had to support L