Scroll to a step isn't working when "placement: auto"

[pierreonthenet]

When placement of a step is set to "auto", the scroll to this step won't work : we need to set it to top, bottom, left or right.
If "auto" is set, then it will scroll to 0 (the top of page).

Here is the code in Tour.prototype._scrollIntoView (v0.12.0) :

      scrollTop = 0;
      switch (step.placement) {
        case 'top':
          scrollTop = Math.max(0, offsetTop - (windowHeight / 2));
          break;
        case 'left':
        case 'right':
          scrollTop = Math.max(0, (offsetTop + height / 2) - (windowHeight / 2));
          break;
        case 'bottom':
          scrollTop = Math.max(0, (offsetTop + height) - (windowHeight / 2));
      }
      this._debug("Scroll into view. ScrollTop: " + scrollTop + ". Element offset: " + offsetTop + ". Window height: " + windowHeight + ".");

[MrLewk]

Just came across this issue, as it's been bugging me for days now. Hopefully a fix can be put in as anything I've tried has failed so far :(