Aims to address http://opensimulator.org/mantis/view.php?id=6355
As part of this work, an incomplete IXGroupsData was added which currently only allows store/fetch/delete of group records
(i.e. no membership data etc)
This is subject to change and currently only an in-memory storage implementation exists for regression test purposes.
While implementing this, a bug was fixed in scene setup helpers where module RegionLoaded() was called immediately after AddRegion() instead of waiting for all AddRegions() to complete.
Also, XmlRpcGroupsModule non-message functionality will now work without a message transfer module (as indicated in the comments but with a contradictory implementation)