gis voroni / delauney options

[burritojustice]

• add --token support to read from third party spaces

• add property search, --search 'p.ZIP=94110', so only the selected points are used in the operation

• add the ability to clear the existing associated voronoi/delaunay space
  here xyz gis spaceID --voronoi --clear (clears the space but keeps the link to the output space)
  here xyz gis spaceID --voronoi --delete (deletes the space and removes the link)

• add --newspace option to send output to a completely new space, instead of the default associated with the data space