Added @return javadoc clause to DBSession.createDBObject() methods
Comment reformat in GanymedeSession.setDefaultOwner javadoc
Make DBSession.createDBObject() take a List<Invid> rather than Vector<Invid>
Made DBPermissionManager use List instead of Vector when possible

Made the newObjectOwnerInvids and the visibilityFilterInvids Lists
unmodifiable for hygiene.
Made GanymedeSession work with the new List-ified DBPermissionManager
Tweaked javadoc for DBPermissionManager.getAvailablePersonae()
Added a handy getObjectHook() shortcut method on DBObject
Updated a comment in GanymedeSession.selectPersona()
Simplified various server code to use new DBObject.getObjectHook() method
Made DBPermission getUser() and getPersona() package protected
Cleaned up personaName and userName handling a bit in DBPermissionManager
DBLog.sendSysEventMail() should always use event targets
Tweaked javadoc and parameter name in DBPermissionManager.selectPersona()
Made DBPermission.filterQueries() a bit more cautious with ownerInvids

This change makes sure that another thread in the calling code can't
mess with ownerInvids while we're verifying the persona's permission to
set those ownerInvids
Trivially simplified a few methods in DBPermissionManager
Renamed newPersona in DBPermissionManager.findMatchingAuthenticatedPersona
Make DBPermissionManager.setDefaultOwner() a bit more cautious
Cleaned up a couple of javadocs in DBPermissionManager
Reordered, cleaned up isMemberOfOwnerGroup() and friends in DBPerm..Manager
Took out extraneous check in DBPermissionManager.isMemberOfAllOwnerGroups()