CloudMade/Leaflet — pull request #741 by shintonik (2012-06-19 11:02:23+00:00)
Title: Set the exact z-index of a marker

If the z-index of a marker is set by calling setZIndexOffset the passed value is correctly set
in the options of the marker but the marker itself is redrawn (in _reset) with a different value.
The y position of the marker (pos.y) is added on top of the passed value.

That way it is impossible to set a specific z-index for a marker.