* new MRC: completed implementation of basic MRC functionality (file +...

* new MRC: completed implementation of basic MRC functionality (file + directory creation/deletion/reading/writing). Features like access control and hard links are still missing.
* small bugfix in BabuDB: log replay now works if files have been deleted
* small bugfix in old MRC: using OSD selection policies w/o arguments caused spurious warning log messages
* updated BabuDB metadata mapping document

git-svn-id: https://xtreemfs.googlecode.com/svn/trunk@44 f8528748-c2c0-11dd-ba5c-d3b7c2b3b534