Use GUPnP Mime Type if available

[markdryan]

When dLeyna-renderer hosts a file, it first asks GLib to determine the mime type of the file. This mime type is then used to set the Content Type header in responses to HTTP get requests. dLeyna-renderer also uses gupnp-dlna to compute the DLNA profile of the file being hosted. However, there is a potential problem here as there could be a mismatch between the DLNA profile computed by gupnp-dlna and the mime type computed by glib, particularly if the shared-mime-info database is not available on the target platform. Therefore, it would be better if dLeyna-renderer used the mime type reported by GUPnP-DLNA when available. If not available it could fall back to g_content_type_guess. This will ensure that our mime types and dlna profiles are always in sync and that dLeyna-renderer can provide a mime type even if the shared mime type database is not installed on a device.

[markdryan]

Christophe, since you're working on dLeyna-renderer at the moment, could you take a look at this?

[markdryan]

Fixed by PR #128