Beta 13 - August 2020

This release introduces the ImageSequenceReference schema to OTIO. It adds support for media references that point at sets of files on disk, for example, the rendered EXR frames for a shot. This work was contributed by @apetrynet and @reinecke. It includes RV adapter support.

Additionally, we're starting a restructure of some of the core math libraries built around a more consistent mathematical framework. The first of these changes is shifting to predicates based on Allen's Interval Algebra [https://en.wikipedia.org/wiki/Allen%27s_interval_algebra] .

Big things:
- ImageSequenceReference (@apetrynet and @reinecke) main: #602 #722 w/ #783 #751
- Allen Interval Algebra predicates (@KarthikRIyer) #697
- AAF Reader metadata support #739
- Post adapter write hook added (@apetrynet) #730
- RV native plugin (so that you can read OTIO files from inside RV rather than convert via an adapter to .rvsession files) @avrata and @apetrynet #637

Small things:
- Reverse and dissolve fixes, Wipe transition support was added to the CMX EDL adapter #763 #757 #687
- Fixing up some bugs and algorithms in rationalTime.cpp #755 #721 #692 (@reinecke and @KarthikRIyer)
- Tox changed and our setup.cfg was altered to conform with the new standard
- otioview enhancement: double click to see full track name (@KarthikRIyer) #690
- conform.py example now prints support file suffixes (@TheBigSasha) #676
- FCP7 adapter bug fixes #674
- xges adapter markers and effects support (@hwilkes-igalia) #609
- Fix bugs in the kdenlive adapter (@vpinon) #714
- bumped pin of PyAAF2 version to 1.4.0 #738
- bug fixes in Markers #740 and #592 (@elabrosseRodeofx)

Project related things:
- added issue templates to the github repo #768
- cleaned up developer quickstart documentation #717
- documentation was broken on read the docs, this was fixed #715