The last pure python release of OpenTimelineIO

Public beta (AcademySoftwareFoundation#140)

* Getting LICENSE.txt, etc. ready for public beta.
* Added reference to EDL SMPTE spec in README.
* Adding CLA PDFs
* Updated CLA PDFs.
* Added license header to all .py source files.

* Small fixes so you can use different versions of Qt.
* Fix to otioview when a timeline is empty.
* Show the OTIO JSON in the details pane.
* Try to guard against missing media_reference.available_range.
* Lots of cleanup, pep8, doc strings, etc.
* Add has_feature to adapter

Change plurality of assert for python3.5.

simple otio viewer (AcademySoftwareFoundation#52)

* simple otio viewer

* - maintains namespaces when importing
- uses .format in favor of % for string formatting
- queries adapter manifest for available file extensions

* Moves otio view widget into its own library

* make otioview executable

Addressed python3 support. resolves AcademySoftwareFoundation#19 (Aca…

…demySoftwareFoundation#32)

* Addressed python3 support. resolves AcademySoftwareFoundation#19

* Added unitests for comparison of TimeRange and TimeTransform and fixed inequality checks

* Added python3.5 to README and converted from io import StringIO to import io

Initial alpha release for evaluation by invite-only community.