Changelog:
- Fixed a cache shrinking issue.
- Fixed a crash when removing a message handler without a free function.
- Fixed an extremely rare threading issue only affecting fmparallelrequests filters and arframeready events.
- Fixed lut and lut2 triggering a fatal error when invalid planes were specified.
- Fixed property append operations on non-empty keys not properly copying the underlying data.
- Fixed wave64 headers generated by avfs.
- Fixed crash in averageframes with odd number of clips.
- Scale averageframes for integer chroma by distance from grey.
- Several fixes and improvements regarding handling of the active script environment in Python.
- Plugin loading now has better error messages.
- Using get_core() in Python now generates a deprecation warning since it's been deprecated for years.