Mix G-code files python script

mixgcode.py

Mix some *.gcode file,
the layer with same height (z value) is collected from different gcode files, put this same height code into one layer.

1. Input gcode files must have same layer height set.
2. When is translating, don't lift the z axis.
3. Can use the retraction.
4. Use slic3r software tool.
5. input1.gocode(file1(fa)) is tallest then input2.gcode
6. G-code file, E must use absolute positions(M82), not use relative positions(M83)

usage: py mixgcode.py output.gcode input1.gcode input2.gcode
Auther: WangJinLong 王金龙
Data: 2015-08-14

The G-code file's head part use the input1.gcode file's head part.
The file1 has the tallest part.