fix "Non-Plastic Parts" for machine base, work bed, smooth rod, and thread rod.
add a M8 nut and two screws for Y_nut_holder
1. refactor module rod
2. move Z threaded rod from X_carriage.scad to Z_carriage.scad because it is stick to Z_carriage.
fix compile WARNING: Ignoring unknown variable 'length'.
fix compile WARNING: Imported file (../libs/Write/orbitron.dxf) found in document root instead of relative to the importing module. This behavior is deprecated
refactor Z smooth rods generation
non plastic parts for X_carriage
add PCB Machining Vise (http://www.thingiverse.com/thing:63578) to hold PCB board
Merge carlosgs' master branch
Re-formating "Non-Plastic Parts" messages from console.
It's easier to be processed in Excel to figure out quantity of each part.
fix redundant message
Merge pull request #9 from glenchung/master

Latest assembly renders