Arrow isn't centered correct because of bubble border

[Spenhouet]

If you set arrowOffset to "center" and the bubble has a border, the arrow is not centered correct.

Minimal example: http://fiddle.jshell.net/x62303x6/

The bubbleBoundingWidth / bubbleBoundingHeight is from el.offsetWidth / el.offsetHeight and does include the border but the arrow position is set relative to the bubble content (without border).

Line 684 in dist:

arrowEl.style[arrowPos] = Math.floor((bubbleBoundingWidth / 2) - arrowEl.offsetWidth/2) + 'px';

Line 694 in dist:

arrowEl.style.top = Math.floor((bubbleBoundingHeight / 2) - arrowEl.offsetHeight/2) + 'px';