XD-282 limiting CDK/Avro Snappy version 1.1.0 upgrade to testRuntime
XD-282 adding runtime override for CDK/Avro Snappy version 1.1.0 for spring-xd-hadoop
Rename CompositeModuleRegistry to DelegatingMR
Add support for Spring Boot.

* Create spring-xd-exec project which build executable jar.
* Add Cloudfoundry manifest.
* Add cloud profile
* The'legacy' profile contains old definitions for non-boot use and will
  be removed, along with 
* Create Spring boot application classes. Legacy 'main' classes will also
  be removed later.
Javadoc fixes.
XD-956: Parser refactoring