Editing commands

[ggarra13]

This commit is for:

Implements #1649.
Makes PR #1518 obsolete.

It implements edit commands in the otio::algo:: namespace. The commands implemented are those discussed in #711.

They are further explained more clearly in:
https://github.com/mccartnm/OpenTimelineIO/blob/openedit_design/docs/design/editorial_design.md

Summarize your change.

It implements the needed base commands for editing with otio, building on top of @darbyjohnston's PR.

@darbyjohnston 's PR #1518 was the base for it, but I debugged two subtle precision bugs in his code and moved it all to the algo:: namespace.

Implementation also modifies errorStatus.h/cpp to add NOT_A_GAP enum.

Implementation, as @darbyjohnston's, makes Composition's protected _index_of_child a now public member of the API as index_of_child and updates track.cpp accordingly.

Reference associated tests.

test_editAlgorithm.cpp is added as in @darbyjohnston, but with tests for all commands.

[codecov-commenter]

Codecov Report

Merging #1651 (ea0e841) into main (eaf8569) will decrease coverage by 0.01%.
The diff coverage is 23.07%.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1651      +/-   ##
==========================================
- Coverage   79.91%   79.90%   -0.01%     
==========================================
  Files         197      197              
  Lines       21731    21733       +2     
  Branches     4339     4340       +1     
==========================================
  Hits        17366    17366              
- Misses       2213     2215       +2     
  Partials     2152     2152              

Flag	Coverage Δ
py-unittests	79.90% <23.07%> (-0.01%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files Changed	Coverage Δ
src/opentimelineio/composition.h	41.37% <ø> (ø)
src/opentimelineio/errorStatus.cpp	28.33% <0.00%> (-0.98%)	⬇️
src/opentimelineio/errorStatus.h	86.95% <ø> (ø)
src/opentimelineio/track.cpp	52.85% <0.00%> (ø)
src/opentimelineio/composition.cpp	47.58% <30.00%> (ø)

---

Continue to review full report in Codecov by Sentry.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update eaf8569...ea0e841. Read the comment docs.

[meshula]

In case you're wondering, the DCO check fail is complaining because some commits lack the DCO line in the commit message. For example, in Darby's initial commit you can see

Signed-off-by: Darby Johnston [email protected]

if you rewrite the commit messages with your own signoff, and force push to your branch, it will clear up the DCO warning in the CI.