Beta 16

[meshula]

I propose that since there are still a number of steps remaining to a 1.0 release (https://github.com/AcademySoftwareFoundation/OpenTimelineIO/projects/14) that we do a Beta 16 release at the point that the repository refactoring is complete.

This would give us a check point of a major structural change and a chance to deal with any technical ramifications while other outstanding elements of the 1.0 project, such as a better website, incubate.