Fix MediaReference after switch to new Timing interface

This was broken by 5ee65b94527a1c0808d89f2ba229d88303310332 and following commits.

Also fix the test after the switch to the new testing framework.
Fix MediaReference to stop the media when detached from its Player
Merge pull request #316 from steveblock/mediaRefSubmission

Fix MediaReference after switch to new Timing interface