Geocode specs

Pull this after `nav` and `stub-net`, or look [here](https://github.com/johnnymo87/LocalSupport/compare/stub-net...geocode-specs) to see the real diff.

`map.feature` is misleading because it makes no real assertions about the map, as the map is not present in the DOM, and thus invisible to cucumber. However, the cuke does make useful assertions about (1) `gmaps4rails` inserting scripts into the DOM to interact with the Google Maps API, and (2) geocoding. Since neither of these are visible in the UI, I've moved assertions about their nature to RSpec.
* assertions about `gmaps4rails` scripts moved to the view spec for `organizations/index`
* assertions about geocoding moved to the model spec for `organizations`, consolidated with what geocoding specs are already present there