fakesrc: remove custom marshaller
fakesrc: remove custom marshaller

Remove our custom marshaller.
Make the buffer in the handoff signal static_scope so that it is actually
writable.

collects/gstreamer,mparis/gstreamer,surround-io/gstreamer,mparis/gstreamer,justinjoy/gstreamer,centricular/gstreamer,jpakkane/gstreamer,krieger-od/gstreamer,justinjoy/gstreamer,cfoch/gstreamer,StreamUtils/gstreamer,shelsonjava/gstreamer,centricular/gstreamer,cablelabs/gstreamer,cfoch/gstreamer,collects/gstreamer,ensonic/gstreamer,centricular/gstreamer,jpakkane/gstreamer,krieger-od/gstreamer,surround-io/gstreamer,krichter722/gstreamer,cfoch/gstreamer,krieger-od/gstreamer,collects/gstreamer,shelsonjava/gstreamer,StreamUtils/gstreamer,lubosz/gstreamer,cfoch/gstreamer,ensonic/gstreamer,krichter722/gstreamer,centricular/gstreamer,surround-io/gstreamer,krichter722/gstreamer,krichter722/gstreamer,jpxiong/gstreamer,Lachann/gstreamer,jpxiong/gstreamer,shelsonjava/gstreamer,Lachann/gstreamer,StreamUtils/gstreamer,cfoch/gstreamer,lovebug356/gstreamer,jpxiong/gstreamer,shelsonjava/gstreamer,mparis/gstreamer,krieger-od/gstreamer,Lachann/gstreamer,justinjoy/gstreamer,shelsonjava/gstreamer,lubosz/gstreamer,ensonic/gstreamer,lovebug356/gstreamer,StreamUtils/gstreamer,lubosz/gstreamer,surround-io/gstreamer,lovebug356/gstreamer,cablelabs/gstreamer,jpakkane/gstreamer,mparis/gstreamer,StreamUtils/gstreamer,collects/gstreamer,lovebug356/gstreamer,lubosz/gstreamer,collects/gstreamer,justinjoy/gstreamer,Lachann/gstreamer,Lachann/gstreamer,cablelabs/gstreamer,centricular/gstreamer,jpxiong/gstreamer,surround-io/gstreamer,ensonic/gstreamer,jpxiong/gstreamer,lovebug356/gstreamer,justinjoy/gstreamer,jpakkane/gstreamer,mparis/gstreamer,krichter722/gstreamer,cablelabs/gstreamer,krieger-od/gstreamer,lubosz/gstreamer,ensonic/gstreamer,jpakkane/gstreamer,cablelabs/gstreamer