Update README
Update README

- new date
- add VP9 to the title
- update list of available targets

Change-Id: I56263336db393020bac5da8e42fbac3a276ffb1f

jdm/libvpx,pcwalton/libvpx,zofuthan/libvpx,ShiftMediaProject/libvpx,mbebenita/aom,jdm/libvpx,goodleixiao/vpx,GrokImageCompression/aom,VTCSecureLLC/libvpx,kalli123/webm.libvpx,sanyaade-teachings/libvpx,kleopatra999/webm.libvpx,gshORTON/webm.libvpx,kim42083/webm.libvpx,matanbs/vp982,VTCSecureLLC/libvpx,webmproject/libvpx,ittiamvpx/libvpx,goodleixiao/vpx,abwiz0086/webm.libvpx,altogother/webm.libvpx,goodleixiao/vpx,liqianggao/libvpx,kalli123/webm.libvpx,gshORTON/webm.libvpx,Laknot/libvpx,Laknot/libvpx,turbulenz/libvpx,matanbs/vp982,zofuthan/libvpx,iniwf/webm.libvpx,GrokImageCompression/aom,Laknot/libvpx,Distrotech/libvpx,matanbs/webm.libvpx,Distrotech/libvpx,stewnorriss/libvpx,Suvarna1488/webm.libvpx,n4t/libvpx,Maria1099/webm.libvpx,WebRTC-Labs/libvpx,webmproject/libvpx,VTCSecureLLC/libvpx,ittiamvpx/libvpx-1,kim42083/webm.libvpx,reimaginemedia/webm.libvpx,jacklicn/webm.libvpx,goodleixiao/vpx,matanbs/webm.libvpx,shyamalschandra/libvpx,iniwf/webm.libvpx,mbebenita/aom,openpeer/libvpx_new,goodleixiao/vpx,liqianggao/libvpx,hsueceumd/test_hui,reimaginemedia/webm.libvpx,pcwalton/libvpx,GrokImageCompression/aom,cinema6/libvpx,Distrotech/libvpx,abwiz0086/webm.libvpx,felipebetancur/libvpx,Topopiccione/libvpx,Acidburn0zzz/webm.libvpx,n4t/libvpx,altogother/webm.libvpx,smarter/aom,kalli123/webm.libvpx,gshORTON/webm.libvpx,liqianggao/libvpx,running770/libvpx,shareefalis/libvpx,mwgoldsmith/vpx,mwgoldsmith/libvpx,matanbs/webm.libvpx,mwgoldsmith/libvpx,webmproject/libvpx,matanbs/vp982,shacklettbp/aom,thdav/aom,shacklettbp/aom,hsueceumd/test_hui,ShiftMediaProject/libvpx,hsueceumd/test_hui,sanyaade-teachings/libvpx,turbulenz/libvpx,shareefalis/libvpx,stewnorriss/libvpx,WebRTC-Labs/libvpx,shacklettbp/aom,mwgoldsmith/vpx,kalli123/webm.libvpx,ittiamvpx/libvpx-1,kim42083/webm.libvpx,ShiftMediaProject/libvpx,ittiamvpx/libvpx-1,charup/https---github.com-webmproject-libvpx-,jdm/libvpx,kleopatra999/webm.libvpx,gshORTON/webm.libvpx,pcwalton/libvpx,Suvarna1488/webm.libvpx,mwgoldsmith/vpx,kalli123/webm.libvpx,kleopatra999/webm.libvpx,running770/libvpx,turbulenz/libvpx,charup/https---github.com-webmproject-libvpx-,VTCSecureLLC/libvpx,cinema6/libvpx,Topopiccione/libvpx,lyx2014/libvpx_c,mwgoldsmith/libvpx,Laknot/libvpx,kim42083/webm.libvpx,luctrudeau/aom,sanyaade-teachings/libvpx,jacklicn/webm.libvpx,WebRTC-Labs/libvpx,stewnorriss/libvpx,lyx2014/libvpx_c,kalli123/webm.libvpx,turbulenz/libvpx,altogother/webm.libvpx,mwgoldsmith/vpx,running770/libvpx,luctrudeau/aom,jmvalin/aom,Distrotech/libvpx,altogother/webm.libvpx,jdm/libvpx,kleopatra999/webm.libvpx,matanbs/vp982,Acidburn0zzz/webm.libvpx,running770/libvpx,ittiamvpx/libvpx,shacklettbp/aom,zofuthan/libvpx,n4t/libvpx,n4t/libvpx,ittiamvpx/libvpx-1,webmproject/libvpx,pcwalton/libvpx,webmproject/libvpx,cinema6/libvpx,openpeer/libvpx_new,Acidburn0zzz/webm.libvpx,n4t/libvpx,shyamalschandra/libvpx,luctrudeau/aom,turbulenz/libvpx,iniwf/webm.libvpx,felipebetancur/libvpx,smarter/aom,thdav/aom,kim42083/webm.libvpx,Distrotech/libvpx,sanyaade-teachings/libvpx,lyx2014/libvpx_c,GrokImageCompression/aom,iniwf/webm.libvpx,Maria1099/webm.libvpx,mbebenita/aom,VTCSecureLLC/libvpx,lyx2014/libvpx_c,ittiamvpx/libvpx,matanbs/vp982,turbulenz/libvpx,Suvarna1488/webm.libvpx,ittiamvpx/libvpx-1,smarter/aom,charup/https---github.com-webmproject-libvpx-,Suvarna1488/webm.libvpx,openpeer/libvpx_new,smarter/aom,jmvalin/aom,shyamalschandra/libvpx,kleopatra999/webm.libvpx,running770/libvpx,kleopatra999/webm.libvpx,gshORTON/webm.libvpx,matanbs/vp982,zofuthan/libvpx,thdav/aom,abwiz0086/webm.libvpx,mbebenita/aom,shyamalschandra/libvpx,reimaginemedia/webm.libvpx,WebRTC-Labs/libvpx,felipebetancur/libvpx,cinema6/libvpx,luctrudeau/aom,luctrudeau/aom,Topopiccione/libvpx,thdav/aom,charup/https---github.com-webmproject-libvpx-,ShiftMediaProject/libvpx,mwgoldsmith/vpx,kim42083/webm.libvpx,zofuthan/libvpx,reimaginemedia/webm.libvpx,reimaginemedia/webm.libvpx,shyamalschandra/libvpx,ittiamvpx/libvpx,mbebenita/aom,thdav/aom,Topopiccione/libvpx,mbebenita/aom,jacklicn/webm.libvpx,Topopiccione/libvpx,openpeer/libvpx_new,Maria1099/webm.libvpx,abwiz0086/webm.libvpx,jdm/libvpx,ittiamvpx/libvpx,lyx2014/libvpx_c,iniwf/webm.libvpx,jmvalin/aom,abwiz0086/webm.libvpx,running770/libvpx,charup/https---github.com-webmproject-libvpx-,Maria1099/webm.libvpx,WebRTC-Labs/libvpx,Suvarna1488/webm.libvpx,turbulenz/libvpx,Maria1099/webm.libvpx,lyx2014/libvpx_c,altogother/webm.libvpx,shacklettbp/aom,cinema6/libvpx,liqianggao/libvpx,smarter/aom,stewnorriss/libvpx,openpeer/libvpx_new,Distrotech/libvpx,turbulenz/libvpx,shacklettbp/aom,Acidburn0zzz/webm.libvpx,gshORTON/webm.libvpx,jmvalin/aom,Acidburn0zzz/webm.libvpx,felipebetancur/libvpx,matanbs/vp982,mwgoldsmith/vpx,shareefalis/libvpx,altogother/webm.libvpx,mbebenita/aom,pcwalton/libvpx,smarter/aom,GrokImageCompression/aom,shareefalis/libvpx,shareefalis/libvpx,thdav/aom,Acidburn0zzz/webm.libvpx,stewnorriss/libvpx,jacklicn/webm.libvpx,pcwalton/libvpx,zofuthan/libvpx,luctrudeau/aom,jdm/libvpx,Maria1099/webm.libvpx,shyamalschandra/libvpx,GrokImageCompression/aom,hsueceumd/test_hui,abwiz0086/webm.libvpx,felipebetancur/libvpx,Laknot/libvpx,jmvalin/aom,ShiftMediaProject/libvpx,jacklicn/webm.libvpx,jacklicn/webm.libvpx,ittiamvpx/libvpx,openpeer/libvpx_new,liqianggao/libvpx,felipebetancur/libvpx,hsueceumd/test_hui,jmvalin/aom,matanbs/webm.libvpx,turbulenz/libvpx,cinema6/libvpx,Topopiccione/libvpx,mwgoldsmith/libvpx,reimaginemedia/webm.libvpx,mbebenita/aom,mbebenita/aom,Suvarna1488/webm.libvpx,shareefalis/libvpx,stewnorriss/libvpx,liqianggao/libvpx,ittiamvpx/libvpx-1,matanbs/webm.libvpx,iniwf/webm.libvpx,charup/https---github.com-webmproject-libvpx-,mwgoldsmith/libvpx,sanyaade-teachings/libvpx,VTCSecureLLC/libvpx,webmproject/libvpx,hsueceumd/test_hui,Laknot/libvpx,matanbs/webm.libvpx,goodleixiao/vpx,mwgoldsmith/libvpx,cinema6/libvpx