XD-1060 XD-1182 add hdp20 and shdp M5

Squashed below commits:
- XD-1182 Switching back to hadoop12 as default for build to get all tests to pass
- XD-1182 Updating stub test class to match new method signatures
- XD-1060 XD-1182 Adding hdp20 as Hadoop distro; updating to spring-data-hadoop 2.0.0.M5
XD-1314 Adding new xd-yarn zip distribution

Squashed commit of the following:
- XD-1314 Adding new xd-yarn zip distribution zip to build
  adding empty spring-xd-yarn subproject
XD-1303 JobInstance REST endpoint

- Add ResourceAssembler that builds JobInstanceInfoResource out
of JobInstanceInfo domain object
- Added REST endpoint /batch/instances/{instanceId} that returns
the job instance for a given instanceId
- Updated the existing REST endpoint /batch/jobs/{jobName}/instances
to return jobExecutions along with the given jobInstance
- Refactored Batch controllers
 - Created AbstractBatchJobsController that can be extended by XD batch
job admin controllers
 - Removed NoSuchJobException and used NoSuchBatchJobException by moving
the logic to update message when there is no job name

Use RestController and minor fixes
XD-1303 Fix JobInstanceInfoResource

- Make JobInstanceInfoResource to have the collection of
JobExecutionInfoResource beans instead of JobExecutions