Add activemq-jms-pool managed dependency

Fixes gh-1423
Merge branch '1.1.x'

Conflicts:
	spring-boot-dependencies/pom.xml
Restore repositories section

Restore repositories section accidentally removed during the merge
Revert "Add activemq-jms-pool managed dependency"

This reverts commit bbdfcd4faa9451b656b9f156b53dd40333c3324b.
Merge branch '1.1.x'

Conflicts:
	spring-boot-dependencies/pom.xml
Add Atomikos support classes

Add support classes for the Atomikos JTA library, including:

- A Spring friendly ConnectionFactoryBean and DataSourceBean.
- A PostProcessor to apply "depends-on" ordering automatically.
- A bindable properties class for type-safe configuration.

See gh-947
Add Bitronix support classes

Add support classes for the Bitronix JTA library, including:

- A Spring friendly ConnectionFactoryBean and DataSourceBean with
  support for setting a direct XA source.
- A PostProcessor to apply shutdown ordering automatically.

See gh-947
Add SpringJtaPlatform for Hibernate

Add SpringJtaPlatform Hibernate AbstractJtaPlatform implementation. Also
relocated SpringNamingStrategy to the `hibernate` sub-package.

See gh-947
Add Atomikos and Bitronix JTA auto-configuration

Add auto-configuration for the Atomikos and Bitronix JTA libraries.

See gh-947
Update DataSource auto-configuration to support XA

Update DataSource and JPA auto-configuration to consider XA datasources.

See gh-947
Update JMS auto-configuration to support XA

Update JMS auto-configuration for ActiveMQ and HornetQ to support XA
transactions.

See gh-947
Add Atomikos and Bitronix starter POMs

Add starters for Atomikos and Bitronix JTA libraries.

See gh-947
Add Atomikos and Bitronix JTA samples

Add samples and integration tests for Atomikos and Bitronix JTA.

See gh-947