Refactor the GCode parser to support a wider array of GCode generators, in particular Slic3r.
Add miwucs code for Slic3r compatibility

 - Enhance SKF / MG parsing
 - Add a correct stat object for dual extrusion
 - Fix some stuff
Refactor the double extrusion heuristic for Gcode
Add license and modify README
Update README
Bump 2.3 version