pyges: add registering functions prototypes to ges.override
pyges: add registering functions prototypes to ges.override

cfoch/ges,pitivi/gst-editing-services,pitivi/gst-editing-services,pitivi/gst-editing-services,volodymyrrudyi/gst-editing-services,pitivi/gst-editing-services,freesteph/gst-editing-services,MathieuDuponchelle/PitiviGes,cfoch/gst-editing-services,MathieuDuponchelle/PitiviGes,cfoch/gst-editing-services,cfoch/ges,freesteph/gst-editing-services,volodymyrrudyi/gst-editing-services,cfoch/ges,freesteph/gst-editing-services,MathieuDuponchelle/PitiviGes,cfoch/ges,volodymyrrudyi/gst-editing-services,cfoch/gst-editing-services,MathieuDuponchelle/PitiviGes,cfoch/gst-editing-services