added support for intro.js

Primary support for intro.js has been added as requested in https://github.com/openMF/community-app/issues/338.

I have used the AngularJs directive of intro.js, since our community-app is basically an AngularJs App.
Although there were some problem with intro.js itself, which causes some issues while using it with requireJS. I have already created an issue about the same at https://github.com/mendhak/angular-intro.js/issues/9.

For now, I had to add the intro.js file into the scripts folder and edit it for our needs. As soon as there is a fix in intro.js we can change it.