div:contenteditable update range for everytime focus event is triggered

[g-viet]

ref needim#45

@tje3d It does not work in Safari.
In Safari, I guess when focus event is triggered, window.getSelection() take no range, window.r angeCount = 0, then it can not update range.

el.addEventListener('focus', function () {
      var s = window.getSelection();
      if (!wdtEmojiBundle.ranges[this.dataset.rangeIndex]) {
        wdtEmojiBundle.ranges[this.dataset.rangeIndex] = new Range();
      } else if (s.rangeCount > 0) {
        s.removeAllRanges();
        s.addRange(wdtEmojiBundle.ranges[this.dataset.rangeIndex]);
      }
    });

So I removed if (s.rangeCount > 0)

[tje3d]

Oh, will take a look into soon