Build multiple file types in one go

[julianstirling]

Currently if we want to output an STL, a STEP and a GLB we have to run all cq-cli 3 times. However as main.py runs cadquery to get the build result and then passes it into the codec, it would be possible just to repeat the codec step which should add some speed.

I can imagine semicolon separating should work:

cq-cli --infile /input/path/script.py --outfile /output/path/newfile.step;/output/path/newfile.stl;/output/path/newfile.glb

If the user specifically wanted to set codecs it could be a list that needs to be the same length

cq-cli --codec step;stl;glb --infile /input/path/script.py --outfile /output/path/newfile.step;/output/path/newfile.stl;/output/path/newfile.glb

[jmwright]

@julianstirling Please review #34 to see if it addresses this need.