XD 2306 [updated]

This is an update of https://github.com/spring-projects/spring-xd/pull/1295 to support modules containing spring-module.properties as an alternative to <module-name>.properties.  This change is backward compatible but allows uploads to rename a module without having to rename jarred resource files. 

Also, I deleted the siDslModule.zip and corresponding READMEs rather than update them now. I plan to add siDslModule to spring-xd-samples shortly. At that point we can restore the READMEs with a link to the sample project.