Replace HomeSettings with Presence Model class. Replace SiteSettings with Site Model class. Derive Group Model class from Presence, adding the "home page settings" properties in a Melange site presence to every Group. Patch by: Todd Larsen

# Geo-enabled Sitemap classes.
from django.contrib.gis.sitemaps.georss import GeoRSSSitemap
from django.contrib.gis.sitemaps.kml import KMLSitemap, KMZSitemap