Make select_addon method more general.

Also rename :ignore to :geo_only (more descriptive/specific--we might
introduce other options in the future and :ignore is kind of vague).

lib/geocoder/stores/active_record.rb

@@ -148,9 +148,7 @@ module Geocoder::Store
         distance = full_distance_from_sql(latitude, longitude, options)
         conditions = ["#{distance} <= ?", radius]
         default_near_scope_options(latitude, longitude, radius, options).merge(
-          :select => select_addon(options) +
-            "#{distance} AS distance" +
-            (bearing ? ", #{bearing} AS bearing" : ""),
+          :select => select_clause(options[:select], distance, bearing),
           :conditions => add_exclude_condition(conditions, options[:exclude])
         )
       end
@@ -222,18 +220,22 @@ module Geocoder::Store
           [b[0], b[2], b[1], b[3]
         ]
         default_near_scope_options(latitude, longitude, radius, options).merge(
-          :select => select_addon(options) +
-            "#{distance} AS distance" +
-            (bearing ? ", #{bearing} AS bearing" : ""),
+          :select => select_clause(options[:select], distance, bearing),
           :conditions => add_exclude_condition(conditions, options[:exclude])
         )
       end
 
       ##
-      # Select string to add
+      # Generate the SELECT clause.
       #
-      def select_addon(options)
-        options[:select] == :ignore ? "" : "#{options[:select] || full_column_name("*")}, "
+      def select_clause(columns, distance, bearing)
+        if columns == :geo_only
+          clause = ""
+        else
+          clause = (columns || full_column_name("*")) + ", "
+        end
+        clause + "#{distance} AS distance" +
+          (bearing ? ", #{bearing} AS bearing" : "")
       end
 
       ##