clip: Emit notify signal when setting Clip.layer
clip: Emit notify signal when setting Clip.layer

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