Add continuous integration

[Gadgetoid]

Adds a very basic build of the library using CMake to catch elementary errors.

Very interested in suggestions for how this could be improved- albeit full unit tests and such are probably a folly at this stage.

[Gadgetoid]

@jgarff should probably also mention this will run against your GitHub Actions quota, I believe, so you might want to yay/nay this.

[Macleykun]

Just wondering
But is jgarff still active?
And if not, this pr could be merged? I assume it works on your fork :) ?

[Gadgetoid]

I still have reservations about forcing potentially billable activities upon someone, but even if they're currently fine. I'd definitely like a yay or nay from the source, but I'll rebase to keep this from going totally defunct.

I... can't say that I'm super active at the moment. The Pi shortage really forced a priority shift so my attention has been elsewhere 😬

@jgarff are you out there?

[jgarff]

Sorry guys, I completely missed your comments here. Sorry about that.

[Gadgetoid]

Sorry guys, I completely missed your comments here. Sorry about that.

Story of my life.

As to whether this still works, and is (or ever was) the right approach... I need to find the time to check!