Default Map Type setting on gmap options page is not being stored properly

If you go to admin/settings/gmap and change the Default Map Type setting (internally known as "maptype"), and submit your settings, you will find that the setting doesn't get stored properly, and it goes back to "Map" as the default no matter what you set it to.

The reason (I think) is that the default map type needs to be a top-level setting rather than inside the baselayers array for the map setup code to recognize it. So even though the setting is saved in the DB, maps are not recognizing the setting.

Also, when the settings page comes back after you save the settings, the magic JS that synchs the map preview with the settings on the page doesn't recognize the setting (it is looking at the top level for maptype), so it then sets the drop-down value back to Map.

I have a patch which fixes the problem by moving maptype out of the baselayers section of the settings form array, and up to the top level, which I've attached.