Tooltip has incorrect position when parent element has relative positioning

[just-boris]

When you fix positionig in #115 not considered the case of toolip inside of relative positioned element.
Here is test case http://plnkr.co/edit/B9ZIbO
To fix this, I propose to append an tooltip node directly into the body.

    $document.find('body').append(tooltip);

[joshdmiller]

Thanks for submitting this. There have been several bug reports for this same issue. The one to follow is #139.