v0.2.1

Closes #57

This adds a simple std::cout when launching the demo to print the keybindings to the terminal.

v0.2.0

See #59 for details.

This adds automated workflows to

• build and run unit tests of both the core library and the demo on any push to any branch
• on merge to main:
  • bump the version in the version file according to the version string in the commit messages (#major, #minor, #patch, #none). #minor by default.
  • create a new release and add debian packages as well as tar.gz and zip release
  • run the unit tests against the released packages
  • build and push new docker images for the core library, the demo and the tutorial