update README.md to point to new demo video
update README.md to point to new demo video

allgeek/GoSublime,cdht/GoSublime,simman/GoSublime,alexmullins/GoSublime,anacrolix/GoSublime,DisposaBoy/GoSublime,DisposaBoy/GoSublime-next,FWennerdahl/GoSublime,allgeek/GoSublime,nathany/GoSublime,nathany/GoSublime,anacrolix/GoSublime,DisposaBoy/GoSublime-next,cdht/GoSublime,justinfx/GoSublime,Mistobaan/GoSublime,DisposaBoy/GoSublime-next,justinfx/GoSublime,anacrolix/GoSublime,allgeek/GoSublime,FWennerdahl/GoSublime,cdht/GoSublime,nathany/GoSublime,dlclark/GoSublime,Mistobaan/GoSublime,FWennerdahl/GoSublime,simman/GoSublime,Mistobaan/GoSublime,dlclark/GoSublime,DisposaBoy/GoSublime,alexmullins/GoSublime,simman/GoSublime,alexmullins/GoSublime