Add more fine-grained check levels #78
Description
As of now, the check is binary. This requires the outputs to be pixel-perfect, whereas reality might require a human reviewer to make that call. Therefore we should discuss to loosen the binary nature of the check and...
- consider adding different result levels, better distinguishing
- consider not requiring images to be pixel perfect - can the checker distinguish between grayscale changes and completely different curves in a graph?
- consider allowing reviewers to override a result (transparently), maybe with a specific status
check_overruled?