Allow import of shapefiles with empty features.
Allow import of shapefiles with empty features.

If a feature lacks a geometry, cope with this and import the feature instead of
dying trying to access the non-existent geometry. Fixes #131.

Code4SA/mapit,chris48s/mapit,opencorato/mapit,Code4SA/mapit,chris48s/mapit,Sinar/mapit,opencorato/mapit,Sinar/mapit,opencorato/mapit,chris48s/mapit,Code4SA/mapit