added Album#subtitle method - in show API this field contains summary

lib/picasa/presenter/album.rb

@@ -46,7 +46,13 @@ def title
 
       # @return [String]
       def summary
-        @summary ||= safe_retrieve(parsed_body, "summary") || safe_retrieve(parsed_body, "subtitle")
+        @summary ||= safe_retrieve(parsed_body, "summary")
+      end
+
+      # Picasa API is not consistent - in show API this field contains summary
+      # @return [String]
+      def subtitle
+        @subtitle ||= safe_retrieve(parsed_body, "subtitle")
       end
 
       # @return [String]

test/api/album_test.rb

@@ -107,6 +107,10 @@
       assert_nil @album.summary
     end
 
+    it "has subtitle" do
+      assert_equal "Opis albumu", @album.subtitle
+    end
+
     it "has rights" do
       assert_equal "public", @album.rights
     end
@@ -260,7 +264,7 @@
     it "creates album" do
       VCR.use_cassette("album-create") do
         attributes = {:title => "gem-test", :summary => "created from test suite <&>", :access => "protected",
-                      :location => "Gilowice", :keywords => "test"}
+          :location => "Gilowice", :keywords => "test"}
         album = Picasa::API::Album.new(:user_id => "w.wnetrzak@gmail.com", :authorization_header => AuthHeader).create(attributes)
 
         assert_equal "gem-test", album.title

test/api/album_update_test.rb

@@ -12,7 +12,7 @@
         original_timestamp = album.timestamp
 
         album = api.show(album.id)
-        assert_equal "created from test suite", album.summary
+        assert_equal "created from test suite", album.subtitle
 
         album = api.update(album.id, :summary => "updated")
 
@@ -24,7 +24,7 @@
         album = api.show(album.id)
 
         assert_equal "Sydney", album.location
-        assert_equal "updated", album.summary
+        assert_equal "updated", album.subtitle
         assert_equal "protected", album.access
 
         new_timestamp = 1385553052