Related to #18. Deregister SqlSession from TX in beforeCompletion
because afterCompletion may be called from a different thread.
Related to #18. Added a JTA scenario with Atomikos
Related to #18. Testing explicit XA rollback.
License headers
Playing with Atomikos properties to see if we can reproduce Weblogic's
behavior but no success so far :(
Fixing xml xsd declarations
Fixes #19. No longer use a default DatabaseIdProvider. And some docs.