Fixed the duplicate slots view.
The script would not clear the screen upon recalculation also the list of duplicates would increase with every iteration because the variables weren't properly reset.
Patch by: Merio Ferraro, Lennard de Rijk
Reviewed by: to-be-reviewed
# Want to get everything from the 'normal' models package.
from django.db.models import *
# The GeoManager
from django.contrib.gis.db.models.manager import GeoManager
# The GeoQ object
from django.contrib.gis.db.models.query import GeoQ
# The geographic-enabled fields.
from django.contrib.gis.db.models.fields import \
GeometryField, PointField, LineStringField, PolygonField, \
MultiPointField, MultiLineStringField, MultiPolygonField, \
GeometryCollectionField
# The geographic mixin class.
from mixin import GeoMixin