New features

Experimental PureData integration with a new libpd-based process - try the PureData process or drop a patch.
To send / receive messages, simply name them [r $0-theInputName] or [s $0-theOutputName] in the Pd patch.
See https://vimeo.com/529042247
ArtNet fixture support ! Thanks to https://github.com/OpenLightingProject/open-fixture-library
Port protocols for execution on top of the ASIO event loop:
- Network messages should use less ressources.
- This will enable new use cases and will help integration of score as a player in separate software.
- Note: for now this has not yet been done for OSCQuery, please test the other protocols (MIDI, ArtNet, "normal" OSC) !
  https://vimeo.com/530753864
Add a few RemoteControl messages (see the doc), to help iscore-pfa/qml-remote
macOS releases should now work on any 10.13 mac.

Improvements / bugfixes

score is now able to build against Qt 6. There are a few regressions remaining.
Fix that video thumbnails would not appear when a video was dropped.
Fix issues with automations rescaling and creating curves when the value was not changing.
Fix that rapidjson would silently output nothing when a value was a NaN.
Don't make automations disappear when their parent is rescaled to zero
Fix that it was possible to merge the end state of an interval with another state
Fix devices needing to be reconnected asynchronously
Fix a sound node issue when adding / removing a looped soundfile during exec
Reinstate freetype on macOS as the upstream crash in Qt seems to have been fixed important if you have weird crashes on macOS please make a bug report ! And try removing qt.conf in score.app/Contents/Resources
Fix build with LLVM 12
Fix #1127 #1163