dashdemux: use MPD.Location element for manifest URL if present
Submitted by A Ashley
The DVB DASH specification section 10.11 states:
Players shall use the MPD.Location element URL for all MPD updates and not the URL used to initially retrieve the MPD.
This bug ticket is to request addition of code in dashdemux check if any Location elements are present in the manifest and use one of these to set the URL that is used for the next manifest refresh.