Switched to pretty (kicad_mod) format as default

[DavidMenting]

Kasbah's suggestion #8 to set the new kicad_mod (pretty) format as a default output seems to make sense. This one-liner fixes that.

[mtl]

Thank you for the pull request.

It makes sense to me too, though I don't know if anyone is depending on the current behavior, which makes me reluctant to introduce the change in the absence of a compelling or urgent need.

I'll leave this open in case someone wants to make a stronger case in support of this change.

[kasbah]

I think it's a mistake to let backwards compatibility prevent you from making improvements like this.

The changes I suggested in #8 (except for the PyPy one, without PyPy actually seems fine for most things) are only small improvements but they do make the user experience a little bit more pleasant.

I would suggest to improve the interface a bit and then release as a package on PyPI. This would also make it easier to install and prevent issues like #11. Going forward you could then use semantic versioning of the package to ensure that people that rely on the command-line interface can pin their version accordingly.

[DavidMenting]

There is no real reason to generate new footprints in the old format any more. Also, you are not removing backward compatibility because the old format is still available. I think it makes sense to make the default output format always track the current one.

If anyone depends on svg2mod generating old KiCad footprints by default, they are unlikely to pull the latest version of svg2mod from GitHub anyway.

[brainstorm]

+1 for switching to the new format by default, @mtl, please merge this.