Modernize the dev and build experience

[filmil]

Would you be open to modernizing the dev and build experience a bit, e.g. by using regular dependency management or some such, and adding github actions workflow for testing and releasing?

[filmil]

In case this is of interest, I have a setup that automatically builds artifacts for Linux and Mac, and uploads to releases when a new release is created. This can be done easily in the github UI, takes a few seconds to do.

See here: https://github.com/filmil/private_comments/releases/tag/v2.0.5

(the release tag versions are bogus, I was just trying things out, it took some trial-and-error to get things just right.)