Set User-Agent in Geocoder requests; delete custom nominatim lib.

Nominatim-the-service's license requires that we identify ourselves.
The custom nominatim lib is no longer required since Geocoder is now
Fast Enough.

config/initializers/geocoder.rb

@@ -1,5 +1,10 @@
 Geocoder.configure(
-  :units => :km
+  :units => :km,
+  :http_headers => {
+    "User-Agent" =>
+      "#{Growstuff::Application.config.user_agent} #{Growstuff::Application.config.user_agent_email}",
+    "From" => Growstuff::Application.config.user_agent_email
+  }
 )
 # This configuration takes precedence over environment/test.rb
 # Reported as https://github.com/alexreisner/geocoder/issues/509

config/initializers/nominatim.rb

@@ -1,4 +0,0 @@
-require 'nominatim'
-
-Nominatim.user_agent = Growstuff::Application.config.user_agent
-Nominatim.user_agent_email = Growstuff::Application.config.user_agent_email

lib/nominatim.rb

@@ -1,43 +0,0 @@
-require 'open-uri'
-require 'json'
-
-class Nominatim
-
-  # class-level instance variable, see
-  # http://www.railstips.org/blog/archives/2006/11/18/class-and-instance-variables-in-ruby/
-  class << self
-    attr_accessor :in_testing
-    attr_accessor :user_agent
-    attr_accessor :user_agent_email
-  end
-  @in_testing = false
-
-  def self.geocode(place)
-    if self.in_testing
-      return stubs[place]
-    end
-    json = open(
-      URI.escape("http://nominatim.openstreetmap.org/search/#{place}?format=json&limit=1"),
-      "User-Agent" => user_agent,
-      "From" => user_agent_email
-    ).read()
-    location = JSON.parse(json)
-    if location && location[0]
-      return {
-        :latitude => location[0]['lat'],
-        :longitude => location[0]['lon'],
-        :boundingbox => location[0]['boundingbox'],
-      }
-    else
-      return nil
-    end
-  end
-
-  def self.stubs
-    @stubs ||= {}
-  end
-
-  def self.add_stub(query_text, results)
-    stubs[query_text] = results
-  end
-end