views: trap errors in lookupId

Return a HttpResponseBadRequest when the place is missing.

Signed-off-by: Ramkumar Ramachandra <artagnon@gmail.com>
views: trap errors in lookupId, lookupToken, lookupBounds

Return a HttpResponseBadRequest when the data is malformed, or the
place is missing.

Signed-off-by: Ramkumar Ramachandra <artagnon@gmail.com>
settings: disable CSRF middleware

Disable the CSRF middleware so that we can POST a payload without a
CSRF token.

Signed-off-by: Ramkumar Ramachandra <artagnon@gmail.com>
views: complete createNew and editId

To construct a PointField from a (latitude, longitude), use a
GEOSGeometry constructor in createNew.  editId is simple enough.
Currently tested only with complete POST data.

Signed-off-by: Ramkumar Ramachandra <artagnon@gmail.com>
urls, views: connect the /attach endpoint to addToken

addToken adds a PlaceToken to an existing Place.

Signed-off-by: Ramkumar Ramachandra <artagnon@gmail.com>