Builder for SpringApplication and ApplicationContext instances with
convenient fluent API and context hierarchy support. Simple example
of a context hierarchy:

   new SpringApplicationBuilder(ParentConfig.class)
               .child(ChildConfig.class).run(args);

Another common use case is setting default arguments, e.g.
active Spring profiles, to set up the environment for an application:

     new SpringApplicationBuilder(Application.class).profiles("server")
 		.defaultArgs("--transport=local").run(args);

If your needs are simpler, consider using the static convenience
methods in SpringApplication instead.

[#49703716] [bs-116] Parent context for some beans maybe?

[Fixes #57949108] [bs-323] Make sure /trace shows error responses

Fixes #62

... and ServerProperties.Tomcat.maxThreads to conveniently
limit the thread pool size in the Connector.

- If RabbitTemplate is on the classpath, turn on autodetection.
- Create a RabbitTemplate, a Rabbit ConnectionFactory, and a RabbitAdmin is spring.rabbitmq.dynamic:true
- Enable some **spring.rabbitmq** properties like host, port, username, password, and dynamic
- Add tests to verify functionality
- Add Groovy CLI functionality. Base it on @EnableRabbitMessaging. Add spring-amqp to the path.
- Create rabbit.groovy test to prove it all works.
- Make Queue and TopicExchange top-level Spring beans in rabbit.groovy test script

* application.properties support for spring.jms and spring.activemq

* more tests to verify ActiveMQConnectionFactory pooling

* Groovy support and simple sample with activemq

* Groovy detection mechanism is @EnableJmsMessaging annotation

Update SpringBootServletInitializer with separate getConfigClass() and
getAdditionalConfigClasses() methods. This change makes it easier to
use the SpringBootServletInitializer with the common use case of a
single config class.

Update DataSource conditional to ensure that the driver class
can actually be loaded by the DataSource. This fixes an issue when
deploying a classic WAR where `org.apache.tomcat.jdbc.pool.DataSource`
is found the parent classloader but the database driver cannot be loaded
because is included as a local `/lib` dependency.

E.g. in application.properties (for launcher)

foo: Application
loader.main: my.${foo}
loader.path: etc

Adapted to changes in the API in Spring Data Commons which requires to pass in the current Environment into the AnnotationRepositoryConfigurationSource.

Replace all references to 'springsource.org' with the new 'spring.io'
domain.

The `Tomcat.start()` has to happen to initialize the `ServletContext`
but we can immediately stop the connector and then restart it when
the context is finished refreshing. Seems to make curl fail quickly
if an app is slow to start.

Add license and legal information on third party open source software that is part of the CLI distribution

Correct the TravisCI link used for the build status image following the
GitHub organization rename from SpringSource to spring-projects.

* Add ability to detect spring-jms on the path and create a JmsTemplate with
  ActiveMQConnectionFactory
* Create tests showing autoconfigured JmsTemplate with ActiveMQ, but prove it
  backs off if a separate ConnectionFactory exists.
* Add support to spring-boot-cli to that it detects JmsTemplate, DefaultMessageListenerContainer,
  or SimpleMessageListenerContainer, and turns on autoconfiguration as well as
  add proper @Grab's and import statements.
* Write a jms.groovy test showing proper CLI support

Simplify ActiveMQ configuration

Update ActiveMQ to 5.7.0