Resize popover on Safari only when the size of its content doesn't change anymore

We adjust the size of the popover on Safari when its content changes. But for example when removing a node just before adding another node to the DOM, the MutationObserver is triggered twice, and we are adjusting the size twice. And since Safari resizes the popover with a slow animation, this leads to strange effects. In order to fix that, I scheduled a timeout the first time the content changes. So the popover is only resized once when we are done with DOM manipulation.

[Felix Dahlke, 2014-02-27 21:42:17]

LGTM