Update link to jsfiddle example in README
Update link to jsfiddle example in README

I changed the jsfiddle so that the threshold is now 0 instead of 0.2. 
This should make the demo slightly easier to understand.
verbling/react-waypoint,TheNounProject/react-waypoint,nickclaw/react-waypoint,NikolaIliev/react-waypoint,plain-vanilla-games/react-waypoint,brigade/react-waypoint,tobiasquinn/react-waypoint,realestate-com-au/react-waypoint,brigade/react-waypoint