Set up GitHub CI

[tkunic]

Background

Github has several features that make it easy to automatically run tests when pull requests are created, or when new branches are pushed. If you open a pull request, e.g. this one #26

You can see the following message:

Continuous integration has not been set up
GitHub Actions and several other apps can be used to automatically catch bugs and enforce style.

Having this set up would help reduce manual testing load on the team, and give more confidence for accepting PRs. The tests that would be run should/could/do live in tests/ and currently only cover the python implementation of pre and post processing: https://github.com/TsotsosLab/SMILER/tree/master/tests

In the longer term, it'd be nice to eventually cover all of smiler_tools and smiler_matlab_tools with tests.

Acceptance Criteria

• When a PR is submitted, SMILER tests are run.