Space Shuttle simplified 6mm

Remix of https://www.thingiverse.com/thing:1740790

Changes :
* update scale for 6mm plywood (Original version is for 4,8mm ???) (Need a plywood of 220mm x 145mm)
* add space between parts ( I use a 2mm flute)
* Split pocket of main frame (More easy to create gcode with http://jscut.org/jscut.html)
* Add a layer for laser engraving

Gcode file :
* Zero lower left, top of the plywood
* 7mm depth, in two passes
* Cut and plunge at 1200mm/min
* First create pocket and then outside of parts