Support newer OMR format

[fsvgm777]

Fixes #1586.

Also fixes a rounding issue when calculating the total frame count, as it'd result in the total run time being wrong most of the time.

Included are also additional system detection tests to account for the recent format changes.

I've tested it locally, and it works fine.

[fsvgm777]

After a brief discussion on Discord, I am not sure whether the rounding should be changed back (Math.Ceiling) or if the rounding should be kept (with the midpoint rounding changed to AwayFromZero to fix more rounding issues). As the format doesn't exactly have a concept of a frame per se (in fact, from my understanding of the format, it's cycle-based, which can then be converted to seconds), I wouldn't even be opposed to put in a frame rate override. Opinions?

My main thing with changing it back to Math.Ceiling is that it would then result in the wrong run time being displayed on the site (e.g. Skooter would have a run time of 5:41.44 instead of 5:41.42, and I'm more convinced the latter is right, based on how the time is calculated (you end up with 341.42295459339107 seconds after dividing the last key matrix state in that particular movie (1173253276800) by 3579545.0, and then by 960.0).

[MBilderbeek]

I'd approve this if I had the power 🙂