Lens background location is not exact

[TalR98]

There are mistakes in both zoomX and in zoomY.

Current:
zoomX = -Math.floor(relX / $element.width() * (NATIVE_IMG.width * $options.scale) - $options.width / 2);
zoomY = -Math.floor(relY / $element.height() * (NATIVE_IMG.height * $options.scale) - $options.height / 2);

In this mistake state, this is wrong (even in the demo):

While cursor is in the edge of the photo, the lens position has mistake - you can see the cursor position is not on the edge in the zoom, although it was on edge in the photo).

The fix:
zoomX =-6 -Math.floor(relX / $element.width() * (NATIVE_IMG.width * $options.scale) - $options.width / 2);
zoomY =-6 -Math.floor(relY / $element.height() * (NATIVE_IMG.height * $options.scale) - $options.height / 2);
(Just added -6 to each calculation)

Don't really know why tho (LOL) but it works now for every image..

[TalR98]

I guess it's because of the border-width tho (6px solid...). The width is 6 as the offset mistake -6