Feature: Midi - make it possible to handle 'SystemRealTime' events synchronously

[HeckHeckHeckHeck]

Sync more precisely to a Midi clock signal.

[willemOH]

@HeckHeckHeckHeck with your digging into midi clock, do you have any thoughts on this issue?

[HeckHeckHeckHeck]

its just a "back of the envelope" design suggestion prototype. Works for me (perfectly actually). should probably be shaped and polished a bit little after merge.

[TomFrost]

+1 on this -- I've been ripping my hair out why my Seed inexplicably thought my MIDI channel was switching to 9 spontaneously. I just wrote my own fix at https://github.com/electro-smith/libDaisy/compare/master...TomFrost:libDaisy:fix/midi-parser-running-status to detect the RTClock message before the parser resets. I should have looked here first. IMO @HeckHeckHeckHeck 's solution is more elegant, but I'll keep mine here for reference if it's worthwhile to anyone.