README: update for GStreamer >= 1.0.x and VPP features.
README: update for GStreamer >= 1.0.x and VPP features.

01org/iotg-lin-gfx-gstreamer-vaapi,CapOM/gstreamer-vaapi,ceyusa/gstreamer-vaapi,gbeauchesne/gstreamer-vaapi,gbeauchesne/gstreamer-vaapi,GStreamer/gstreamer-vaapi,GStreamer/gstreamer-vaapi,ceyusa/gstreamer-vaapi,01org/iotg-lin-gfx-gstreamer-vaapi,CapOM/gstreamer-vaapi,01org/iotg-lin-gfx-gstreamer-vaapi,CapOM/gstreamer-vaapi,gbeauchesne/gstreamer-vaapi