Added GeoJSON MultiLineString support.

I just forwarded some members of google.maps.Polygon to an internal polygon
array, et voilá. google.maps.event.addListener was replaced by the class' own
addListener (although I am not sure if this is mandatory).
The obvious advantage would be, that all the code below remains almost
unaltered and as comprehensive (haha) as before.
Applied another correction to EPGS:31468.