added npm install to readme
added npm install to readme

collinmesser/esfiddle,collinmesser/esfiddle,joshghent/es6-fiddle-web,asiyani/esfiddle,esfiddle/esfiddle,vcapretz/esfiddle,joshghent/es6-fiddle-web,esfiddle/esfiddle,esfiddle/esfiddle,vcapretz/esfiddle,asiyani/esfiddle