Anchor scroll offset

Can we refactor this into a separate function that we test separately? I would put it unto jQLite and name it `$$readyLoaded` (similar to `ready` but waiting longer). This should be at the place where we add our extensions to jQlite and jQuery (see e.g. `scope()`). The in the tests for `$anchroScroll` we can simply mock out `$$readyLoaded` and the mocked window and mocked document would get a lot simpler.

E.g. 
```
var JQLitePrototype = { ...
  $$readyLoaded: function loaded(callback) {
    if (document.readyState === 'complete') {
      callback();
    } else if (onLoaded.waitingCallbacks) {
      onLoaded.waitingCallbacks.push(callback);
    } else {
      onLoaded.waitingCallbacks = [callback];
      var win =  jqLite($window);
      win.on('load', function unbindAndScroll() {
        win.off('load', unbindAndScroll);
        onLoaded.waitingCallbacks.forEach(function(callback) { callback(); });
        onLoaded.waitingCallbacks = null;
      });
    }
  }
}
```