Get geometries back on the map

This changes the following:
  * Fixes the geometry column name
  * Reprojects the UTM lines to lat/lng
  * Converts geojson to GEOS object before saving to db
That's a great question, it's a subtle effect. Making the constructor private restricts external construction (i.e., the only place it can be created is in the companion object below). Previously, it was possible to call the constructor externally, even though it wasn't actually happening. But now that we have additional logic to be applied on creation (the reprojection), we want to make sure no one attempts to create the object with incorrectly projected lines.