Additional IMSC test content, including SDR and HDR exemplar renders

Good morning/evening,

Quick note to let you know that an additional set of IMSC test content is
available:

https://github.com/w3c/IMSC-1.0.1_Text_TestContent
https://github.com/w3c/IMSC-1.1_Text_TestContent
https://github.com/w3c/IMSC-1.1_Image_TestContent

In particular, this content includes temporal synchronization tests, and
both SDR and HDR exemplar renders.

Best,

-- Pierre