Refactor JDBC node store configuration tests out
Refactor node create JDBC tests into their own file
Refactor out delete node JDBC test
Move node exists JDBC tests to own file
Move affiliations tests to own file
Fix race condition
Merge pull request #173 from surevine/race-condition

Race condition for federation
Added JSPF plugin framework as a dependency
Refactored payload validator code to be less Atom specific

This is in preparation for future support for different payloads.
Made content validation more generic and added validator for IODEF

Removed Atom knowledge from publish processor by:
- Passing generic item element into AtomEntry rather than (Atom specific) entry element
- Pushed local and global ID generation, and in-reply-to getter, into validator
Tidy up unused imports and fields