Rework application configuration

Use a preinitializer to load the settings from application.yml so
that they are available as early as possible. All settings can also
be overridden using environment variables.

The ad-hoc settins in environment.rb are then moved to this new
system so we have one consistent location for settings.

lib/map_boundary.rb

@@ -24,8 +24,8 @@ module MapBoundary
 
     # check the bbox isn't too large
     requested_area = (max_lat-min_lat)*(max_lon-min_lon)
-    if requested_area > APP_CONFIG['max_request_area']
-      raise OSM::APIBadBoundingBox.new("The maximum bbox size is " + APP_CONFIG['max_request_area'].to_s + 
+    if requested_area > MAX_REQUEST_AREA
+      raise OSM::APIBadBoundingBox.new("The maximum bbox size is " + MAX_REQUEST_AREA.to_s + 
         ", and your request was too large. Either request a smaller area, or use planet.osm")
     end
   end

lib/osm.rb

@@ -530,7 +530,7 @@ module OSM
 
   def self.legal_text_for_country(country_code)
     file_name = File.join(RAILS_ROOT, "config", "legales", country_code.to_s + ".yml")
-    file_name = File.join(RAILS_ROOT, "config", "legales", APP_CONFIG['default_legale'] + ".yml") unless File.exist? file_name
+    file_name = File.join(RAILS_ROOT, "config", "legales", DEFAULT_LEGALE + ".yml") unless File.exist? file_name
     YAML::load_file(file_name)
   end
 end

lib/quova.rb

@@ -17,8 +17,8 @@ module Quova
   ##
   # Access details for WSDL description
   WSDL_URL="https://webservices.quova.com/OnDemand/GeoPoint/v1/default.asmx?WSDL"
-  WSDL_USER = APP_CONFIG['quova_username']
-  WSDL_PASS = APP_CONFIG['quova_password']
+  WSDL_USER = QUOVA_USERNAME
+  WSDL_PASS = QUOVA_PASSWORD
 
   ##
   # Status codes