servers - OSD replication:

- new OSD selection policies for RandomAccessFile
- removing a replica also removes the data from the OSDs now
- replication updates its Caps and XLocs, if newer versions have arrived
- ReplicationStressTest could write also holes now
- ReplicaManagement supports new modes for automatic replica adding/removing (random and DNS policies)
- support for logging categories
- more Logging
- TestEnvirement could create multiple OSDs now
- new replication test which is using the RandomAccessFile
- lots of bugfixes

git-svn-id: https://xtreemfs.googlecode.com/svn/trunk@737 f8528748-c2c0-11dd-ba5c-d3b7c2b3b534