Fix uninitialized variable warnings

lib/geocoder/lookups/base.rb

@@ -15,6 +15,9 @@ module Geocoder
   module Lookup
 
     class Base
+      def initialize
+        @cache = nil
+      end
 
       ##
       # Human-readable name of the geocoding API.

lib/geocoder/models/base.rb

@@ -29,7 +29,7 @@ module Geocoder
       private # ----------------------------------------------------------------
 
       def geocoder_init(options)
-        unless @geocoder_options
+        unless defined?(@geocoder_options)
           @geocoder_options = {}
           require "geocoder/stores/#{geocoder_file_name}"
           include Geocoder::Store.const_get(geocoder_module_name)