Add Atomikos and Bitronix JTA samples

Add samples and integration tests for Atomikos and Bitronix JTA.

See gh-947

spring-boot-samples/pom.xml

@@ -38,6 +38,8 @@
 		<module>spring-boot-sample-hornetq</module>
 		<module>spring-boot-sample-integration</module>
 		<module>spring-boot-sample-jetty</module>
+		<module>spring-boot-sample-jta-atomikos</module>
+		<module>spring-boot-sample-jta-bitronix</module>
 		<module>spring-boot-sample-liquibase</module>
 		<module>spring-boot-sample-parent-context</module>
 		<module>spring-boot-sample-profile</module>