panic of GeojsonFeatureAdapter on invalid input

[buckhx]

If the GeojsonFeatureAdapter get non-valid geojson it panics.

Error should be bubbled up

github.com/buckhx/diglet/geo.GeojsonFeatureAdapter(0xc8216d92c0, 0x2)
/home/vagrant/workspace/go/src/github.com/buckhx/diglet/geo/geojson.go:40 +0x89
main.execute.func2(0xc8217be7d0, 0xc8216d9260, 0x7f12f0308620, 0xc820092070)
/home/vagrant/workspace/go/src/github.com/buckhx/gofence/cli.go:82 +0x1e1
created by main.execute
/home/vagrant/workspace/go/src/github.com/buckhx/gofence/cli.go:96 +0xfc

This speaks to the larger issue of removing util.Check() where possible

[buckhx]

fixing in dev now