By request I added new feature – automatic set center and zoom map to show all placemarks.
Here you can see where it is
Before that you can ability manual set zoom and center to show map with its objects. But in browsers on different devices you have different resolution. And you can’t predict what zoom you have to set. But now you can just set this property to Yes, and google maps calculate and set zoom and map center.
You should to know – if you set map centering placemark, or you set open infowin for placemark, then this properties can override expected behavior.