remove unused code
remove unused councils.geojson
fetch and convert ESRI districts, add to map
set global app.districts variable
highlight the selected district
improved code clarity + Mesa districts comment
removed apparently useless line

- district_data wasn’t set/used elsewhere
  and we set response[:in_district] later
fix bug where same lat/lng was always returned

- if the user supplied a lat/lng, use it
mixup to call to pushState

(takes three arguments, not two)