Change the use of a reserved color space entry
Change the use of a reserved color space entry

This commit rename a reserved color space entry to BT_2020, it intends
to provide support for VP9 bitstream to pass along the color space
type defined in BT.2020(Rec.2020)

please note this entry does not have any effect on encoding/decoding
behavior, but allow applications to the pass the information along
from encoding end to decoding end.

Change-Id: I4678520e89141ea5e8900f7bd1c0e95b710b7091

Suvarna1488/webm.libvpx,openpeer/libvpx_new,stewnorriss/libvpx,felipebetancur/libvpx,running770/libvpx,Suvarna1488/webm.libvpx,smarter/aom,gshORTON/webm.libvpx,kleopatra999/webm.libvpx,luctrudeau/aom,mbebenita/aom,altogother/webm.libvpx,goodleixiao/vpx,running770/libvpx,matanbs/webm.libvpx,matanbs/vp982,Distrotech/libvpx,kalli123/webm.libvpx,hsueceumd/test_hui,mbebenita/aom,iniwf/webm.libvpx,kleopatra999/webm.libvpx,smarter/aom,liqianggao/libvpx,openpeer/libvpx_new,Acidburn0zzz/webm.libvpx,gshORTON/webm.libvpx,hsueceumd/test_hui,stewnorriss/libvpx,jacklicn/webm.libvpx,mwgoldsmith/libvpx,abwiz0086/webm.libvpx,Distrotech/libvpx,zofuthan/libvpx,webmproject/libvpx,reimaginemedia/webm.libvpx,altogother/webm.libvpx,kleopatra999/webm.libvpx,openpeer/libvpx_new,ittiamvpx/libvpx-1,running770/libvpx,kim42083/webm.libvpx,openpeer/libvpx_new,mbebenita/aom,Laknot/libvpx,abwiz0086/webm.libvpx,matanbs/webm.libvpx,reimaginemedia/webm.libvpx,matanbs/vp982,GrokImageCompression/aom,Maria1099/webm.libvpx,mbebenita/aom,thdav/aom,jdm/libvpx,Maria1099/webm.libvpx,thdav/aom,matanbs/vp982,Laknot/libvpx,GrokImageCompression/aom,jacklicn/webm.libvpx,pcwalton/libvpx,liqianggao/libvpx,jmvalin/aom,charup/https---github.com-webmproject-libvpx-,gshORTON/webm.libvpx,zofuthan/libvpx,lyx2014/libvpx_c,pcwalton/libvpx,mbebenita/aom,altogother/webm.libvpx,matanbs/webm.libvpx,lyx2014/libvpx_c,Acidburn0zzz/webm.libvpx,ittiamvpx/libvpx-1,ShiftMediaProject/libvpx,goodleixiao/vpx,luctrudeau/aom,Topopiccione/libvpx,ittiamvpx/libvpx-1,jacklicn/webm.libvpx,pcwalton/libvpx,mwgoldsmith/libvpx,zofuthan/libvpx,openpeer/libvpx_new,goodleixiao/vpx,matanbs/webm.libvpx,felipebetancur/libvpx,kim42083/webm.libvpx,liqianggao/libvpx,shareefalis/libvpx,goodleixiao/vpx,shacklettbp/aom,Distrotech/libvpx,lyx2014/libvpx_c,kalli123/webm.libvpx,matanbs/vp982,mwgoldsmith/libvpx,kalli123/webm.libvpx,ShiftMediaProject/libvpx,jmvalin/aom,mwgoldsmith/libvpx,jacklicn/webm.libvpx,iniwf/webm.libvpx,Topopiccione/libvpx,jmvalin/aom,zofuthan/libvpx,mbebenita/aom,thdav/aom,pcwalton/libvpx,VTCSecureLLC/libvpx,matanbs/vp982,shacklettbp/aom,jmvalin/aom,mbebenita/aom,kalli123/webm.libvpx,mwgoldsmith/vpx,GrokImageCompression/aom,charup/https---github.com-webmproject-libvpx-,shacklettbp/aom,gshORTON/webm.libvpx,jmvalin/aom,stewnorriss/libvpx,shareefalis/libvpx,liqianggao/libvpx,shyamalschandra/libvpx,kleopatra999/webm.libvpx,shareefalis/libvpx,jdm/libvpx,mwgoldsmith/vpx,Acidburn0zzz/webm.libvpx,VTCSecureLLC/libvpx,liqianggao/libvpx,reimaginemedia/webm.libvpx,jacklicn/webm.libvpx,ittiamvpx/libvpx-1,matanbs/vp982,hsueceumd/test_hui,reimaginemedia/webm.libvpx,altogother/webm.libvpx,Topopiccione/libvpx,running770/libvpx,webmproject/libvpx,mwgoldsmith/vpx,mbebenita/aom,pcwalton/libvpx,shacklettbp/aom,Maria1099/webm.libvpx,iniwf/webm.libvpx,smarter/aom,stewnorriss/libvpx,stewnorriss/libvpx,mwgoldsmith/vpx,Suvarna1488/webm.libvpx,Maria1099/webm.libvpx,Maria1099/webm.libvpx,jdm/libvpx,matanbs/webm.libvpx,iniwf/webm.libvpx,abwiz0086/webm.libvpx,kalli123/webm.libvpx,GrokImageCompression/aom,shyamalschandra/libvpx,GrokImageCompression/aom,felipebetancur/libvpx,gshORTON/webm.libvpx,thdav/aom,GrokImageCompression/aom,altogother/webm.libvpx,jdm/libvpx,shyamalschandra/libvpx,iniwf/webm.libvpx,zofuthan/libvpx,webmproject/libvpx,ittiamvpx/libvpx-1,running770/libvpx,Suvarna1488/webm.libvpx,charup/https---github.com-webmproject-libvpx-,matanbs/webm.libvpx,hsueceumd/test_hui,Maria1099/webm.libvpx,VTCSecureLLC/libvpx,lyx2014/libvpx_c,abwiz0086/webm.libvpx,jacklicn/webm.libvpx,pcwalton/libvpx,smarter/aom,Distrotech/libvpx,abwiz0086/webm.libvpx,smarter/aom,ShiftMediaProject/libvpx,goodleixiao/vpx,jmvalin/aom,Laknot/libvpx,mbebenita/aom,shyamalschandra/libvpx,webmproject/libvpx,jdm/libvpx,VTCSecureLLC/libvpx,shareefalis/libvpx,ShiftMediaProject/libvpx,mwgoldsmith/vpx,lyx2014/libvpx_c,mwgoldsmith/libvpx,kleopatra999/webm.libvpx,kim42083/webm.libvpx,felipebetancur/libvpx,Laknot/libvpx,shareefalis/libvpx,Acidburn0zzz/webm.libvpx,webmproject/libvpx,shareefalis/libvpx,gshORTON/webm.libvpx,reimaginemedia/webm.libvpx,luctrudeau/aom,Suvarna1488/webm.libvpx,smarter/aom,charup/https---github.com-webmproject-libvpx-,lyx2014/libvpx_c,felipebetancur/libvpx,luctrudeau/aom,zofuthan/libvpx,luctrudeau/aom,jdm/libvpx,Topopiccione/libvpx,shacklettbp/aom,hsueceumd/test_hui,kim42083/webm.libvpx,VTCSecureLLC/libvpx,liqianggao/libvpx,goodleixiao/vpx,Topopiccione/libvpx,stewnorriss/libvpx,hsueceumd/test_hui,running770/libvpx,Suvarna1488/webm.libvpx,shacklettbp/aom,abwiz0086/webm.libvpx,ittiamvpx/libvpx-1,VTCSecureLLC/libvpx,Acidburn0zzz/webm.libvpx,thdav/aom,webmproject/libvpx,matanbs/vp982,iniwf/webm.libvpx,Distrotech/libvpx,Topopiccione/libvpx,openpeer/libvpx_new,Laknot/libvpx,kim42083/webm.libvpx,mwgoldsmith/libvpx,Laknot/libvpx,ShiftMediaProject/libvpx,altogother/webm.libvpx,luctrudeau/aom,shyamalschandra/libvpx,kleopatra999/webm.libvpx,charup/https---github.com-webmproject-libvpx-,thdav/aom,Acidburn0zzz/webm.libvpx,Distrotech/libvpx,kim42083/webm.libvpx,mwgoldsmith/vpx,felipebetancur/libvpx,charup/https---github.com-webmproject-libvpx-,reimaginemedia/webm.libvpx,kalli123/webm.libvpx,shyamalschandra/libvpx