Add some links to README.md, and correction
Add some links to README.md, and correction

ZainRizvi/wordcloud2.js,ZainRizvi/wordcloud2.js,ZainRizvi/wordcloud2.js,alex2wong/wordcloud2.js,alex2wong/wordcloud2.js,timdream/wordcloud2.js,alex2wong/wordcloud2.js,timdream/wordcloud2.js,timdream/wordcloud2.js