Translate code to ES6, add support for named routes instead of selector

[milosb793]

In this pull request, I've added:

1. Refactor ES6
2. Add support for named routes

Example of usage:

Sometimes, we need different name than just element ID, so let's define object like:

let routes = {
   "nav-item1" : "this-is-item1-page",
   "nav-item2" : "this-is-item2-page",
   "nav-item3" : "this-is-item3-page",
};

So instead of #nav-item1 we'll have #this-is-item1-page in URL.

To enable this feature, you can just pass option named routeObject:

$('.nav-tabs').stickyTabs({routeObject : routes});

If this option is not passed, default elements IDs will be used.