ges-uri-source: don't use gnlurisource but a custom bin.
ges-uri-source: don't use gnlurisource but a custom bin.

	+ This bin is a uridecodebin when GES_TRACK_TYPE_VIDEO
	+ This bin contains a uridecodebin and a volume when GES_TRACK_TYPE_AUDIO

pitivi/gst-editing-services,cfoch/gst-editing-services,cfoch/ges,pitivi/gst-editing-services,cfoch/gst-editing-services,pitivi/gst-editing-services,cfoch/ges,cfoch/ges,cfoch/gst-editing-services,cfoch/ges,pitivi/gst-editing-services,cfoch/gst-editing-services