Fix exception while writing utf8 to cache

lib/musicbrainz/client.rb

@@ -9,6 +9,8 @@ module MusicBrainz
     end
 
     def load(resource, query, params)
+      raise Exception.new("You need to run MusicBrainz.configure before querying") if MusicBrainz.config.nil?
+
       response = contents_of(build_url(resource, query))
       xml = Nokogiri::XML.parse(response).remove_namespaces!.xpath('/metadata')
       data = params[:binding].parse(xml)

lib/musicbrainz/client_modules/caching_proxy.rb

@@ -18,12 +18,12 @@ module MusicBrainz
         response = nil
 
         if File.exist?(file_path)
-          response = File.open(file_path).gets
+          response = File.open(file_path, 'rb').gets
         else
           response = super
           unless response.nil? or response.empty?
             FileUtils.mkdir_p file_path.split('/')[0..-2].join('/')
-            File.open(file_path, 'w') do |f|
+            File.open(file_path, 'wb') do |f|
               f.puts response
               f.chmod 0755
               f.close