Update display of audio thumbnails

Submodule islandora_solution_pack_audio 2b8b121..7887995:
  > Merge branch 'cherry-pick-tn-7ae3c7a869' into lyr-master
Submodule islandora_videojs 066c04a..2db9728:
  > Don't double-url() the thumbnail
  > Add troubleshooting note for properly named video.js directory.