OSD-replication:

- multiple fetch-object-requests will be sent for parallel downloads
- simple mechanism for pretending OSD overloading due to sending of multiple requests
- new call for getting objectLists from OSDs (lists of local saved objects) => could be used to determine if replica is full
- some bugfixes

git-svn-id: https://xtreemfs.googlecode.com/svn/trunk@824 f8528748-c2c0-11dd-ba5c-d3b7c2b3b534