libxtreemfs: UUIDIterator changed into an abstract class with two subclasses:...

libxtreemfs: UUIDIterator changed into an abstract class with two subclasses: SimpleUUIDIterator and ContainerUUIDIterator. The first equals the former UUIDIterator, the second is new and was introduced to allow failover when reading a replicated and striped file.

git-svn-id: https://xtreemfs.googlecode.com/svn/trunk@3232 f8528748-c2c0-11dd-ba5c-d3b7c2b3b534