Shapefile creation

[stephenrjones]

When creating Shapefiles (Using 'Share your Work' on the Job detail page), an error is encountered when trying to create a shapefile of zero items -- for example, creating a 'Shape Points' shapefile on a Job that has no points currently residing in the job. We should be able to do a quick check to determine if any points/lines/polygons exist, then either create the shapefile if there are items in the job, or else display an error message to the user

[john-kilgo]

In progress. Currently works in several cases but not when there is a job without lines and a user adds lines: causes similar error to occur.