Add a .WithDefaultBroker(...) extension method to BusBuilderConfigurationExtensions

[uglybugger]

Our sample code currently looks like this for non-container installations:

var typeProvider = new AssemblyScanningTypeProvider(Assembly.GetExecutingAssembly());

var messageBroker = new DefaultMessageBroker(typeProvider);

var bus = new BusBuilder().Configure()
                        .WithNames("MyTestSuite", Environment.MachineName)
                        .WithConnectionString(CommonResources.ConnectionString)
                        .WithTypesFrom(typeProvider)
                        .WithCommandBroker(messageBroker)
                        .WithRequestBroker(messageBroker)
                        .WithMulticastEventBroker(messageBroker)
                        .WithCompetingEventBroker(messageBroker)
                        .WithMulticastRequestBroker(messageBroker)
                        .WithDefaultTimeout(TimeSpan.FromSeconds(10))
                        .Build();

It would be nice if it could look like this instead:

var typeProvider = new AssemblyScanningTypeProvider(Assembly.GetExecutingAssembly());

var messageBroker = new DefaultMessageBroker(typeProvider);

var bus = new BusBuilder().Configure()
                        .WithNames("MyTestSuite", Environment.MachineName)
                        .WithConnectionString(CommonResources.ConnectionString)
                        .WithTypesFrom(typeProvider)
                        .WithDefaultBroker(messageBroker)
                        .WithDefaultTimeout(TimeSpan.FromSeconds(10))
                        .Build();

[uglybugger]

Wow. That was quick. I'd hardly finished typing before you wrote it :|