[3dprinter-general] Release libarcus and libsavitar

[Gregor Riepl]

Hi Petter,

Could you push the the two packages to the build server?

I didn't tag the release yet as I'm not sure if I caught all C++ symbol
changes for all architectures. Perhaps more changes are needed.

These are semi-urgent, as they're currently FTBS.

If you're unavailable, it would be great if somebody else from 3-D Printing
could push them.

Thank you!
Greg