* controls=panzoom,mouse -- set up different controls. Also allows 'layerswitcher'
* layers=openlayers,nasa -- set up different layers. Only these two are supported at the moment.
* center, zoom, data are all the same as before.
These changes are relevant to Ticket #12.
git-svn-id: http://svn.openlayers.org/trunk/openlayers@360 dc9f47b5-9b13-0410-9fdd-eb0c1a62fdaf