As far as I know, those examples are created while still in alpha version thus some code should be applied differently
Currently I use ionic@beta version, and indeed they use ionic-framework folder instead of just ionic.
Well, since ionic 2 is not stable yet, anything could change
Hoping to see release date for ionic2 as I found this framework is amazing and much more easier to understand (than Ionic 1, I skip Ionic 1 and go straight to Ionic 2).
@kuntal for best practice, I suggest to add template upon starting new app (since most template are working!) as starting point. From there you can go to add page (e.g: from tabs example) by copying page folder and make adjustment on app.js