Allows for filename.srt, filename.en.srt, etc., to be automatically associated with video.mp4 (or whatever) when playing over dlna.
This is the "modern" method, which I've verified to work on VLC and in LG webOS 2. There is a vendor specific mechanism for Samsung that I havn't been able to get working on my F series.
Also made some minor corrections to logging and container IDs.
Mostly trying to get logging to happen through rclone's log methods.
Added request logging, and a trace parameter that will dump the
entire request/response for debugging when dealing with poorly
written clients.
Also added a flag to specify the device's "Friendly Name" explicitly,
and made an attempt at allowing mime types in addition to video.
