Google V2: addOverlay KML error

[adamd]

1. Using Google v2 provider call addOverlay using a KML URL.
2. JavaScript error produced along the lines of "branch" is undefined.

The pertinent line is this...
http://github.com/mapstraction/mxn/blob/master/source/mxn.google.core.js#L295

Google Maps no longer seems to support this second parameter (an "on
overlay loaded" handler, i assume) see the following:
http://code.google.com/apis/maps/documentation/javascript/v2/reference.html#GMap2.addOverlay