Remove pointer-events dependency

Remove the CSS `pointer-events` property dependency for improve compatibility with older browsers.

The problem right now was that the columns are wrapped into a div positioned absolute filling the whole window, and with `pointer-events: none`, later the columns has `pointer-events: all` for disable interaction with the covered content.
 
Please check the where you can use this feature [http://caniuse.com/#feat=pointer-events](http://caniuse.com/#feat=pointer-events).

Also re-add the `sample-app` folder for test the lib in local