New ConfigR acceptance test, RedefiningAnObjectDefinedInLoadedFile, to demonstrate obscure functionality

CascadingConfigurationFeatureRedefiningAnObjectDefinedInLoadedFile.cs

        [Scenario]
        public static void RedefiningAnObjectDefinedInLoadedFile(Foo result)
        {
            "Given a config file containing a Foo with a Bar of 'baz'"
                .Given(() =>
                {
                    using (var writer = new StreamWriter("foo1.csx"))
                    {
                        writer.WriteLine(@"#r ""ConfigR.Features.dll""");
                        writer.WriteLine(@"using ConfigR.Features;");
                        writer.WriteLine(@"Foo foo = new Foo { Bar = ""baz"" };");
                        writer.WriteLine(@"Add(""foo"", foo);");
                        writer.Flush();
                    }
                })
                .Teardown(() => File.Delete("foo1.csx"));

            "And another config file containing a Foo with a Bar of 'bazzzzz' that loads the first config"
                .Given(() =>
                {
                    using (var writer = new StreamWriter("foo2.csx"))
                    {
                        writer.WriteLine(@"#r ""ConfigR.Features.dll""");
                        writer.WriteLine(@"#load ""foo1.csx""");
                        writer.WriteLine(@"using ConfigR.Features;");
                        writer.WriteLine(@"foo.Bar = ""bazzzzz"";");
                        writer.Flush();
                    }
                })
                .Teardown(() => File.Delete("foo2.csx"));

            "When I load the second file"
                .And(() => Config.Global.LoadScriptFile("foo2.csx"));

            "And I get the Foo"
                .And(() => result = Config.Global.Get<Foo>("foo"));

            "Then the Foo has a Bar of 'bazzzzz'"
                .Then(() => result.Bar.Should().Be("bazzzzz"));
        }