Links and marker behavior.

[DimitriChauvel]

Links are displayed behind their arrow marker.
But, we want the links to end at the edge of the marker.

Bad behavior :

I tried subtracting the marker size multiplied by the zoom scale from the link end position, but the offset is incorrect when I manually change the root SVG size.

I tried too putting the links in the #container svg to have the same position repository but it makes it very difficult to get the anchor position for the links.