Check if outside using absolute dimesions

I've been seeing a bug where full images, which are smaller than the flyout in one dimension, are never shown. (for example a 400x2000 image in a 500x500 flyout)

This is the fix I'm now using. The zoomed image is centered across dimesions, in which it is smaller than the window (lines 198-199). The check to see if the mouse has left the target image is then performed using the absolute dimesions of the `$target` and the position of the pointer relative to it.

The build does still need to be run (I don't have access to node at the moment).