zips and shps

Added zipped shapefile support, which also includes general zip support, aka drag and drop a zipfile with a geojson and kml in it.

If that's a bit to ambitious I also have [a version](https://github.com/calvinmetcalf/geojson.io/tree/shapefile) that only allows geojson and shapefiles inside the zipfile and will only return the first one, not parsing the other types avoids reorganizing readfile.