ImageViewer v2 🎉

• It's a complete rewrite of ImageViewer with no jQuery requirement in ES6.
• Fixed lot of bugs from v1.
• Published on the npm. V1 was not available on npm.
• While the options and instance method are same the way you use a ImageViewer and FullScreenView is changed. The v1 API will no longer be supported.
• Changed the package name to iv-viewer. image-viewer name was not available on npm.