Transformation to non-shared event lists is virtually complete:
Events have an ID now, shared among clone parts.
New: Fast pending operations lists: They replace RT "execute/revert ops stage-2".
A few more commands support Undo/Redo now, like setting global tempo.
Handful of (un)related fixes along the way.
Merge branch 'master' of https://github.com/muse-sequencer/muse