servers: added experimental storage layout (single file), OSD can use...

servers: added experimental storage layout (single file), OSD can use different layouts, changed obj version to 64bit (still compatible with old 32bit format), MRC/OSD wait until DIR is available or timeout (issue #90)

git-svn-id: https://xtreemfs.googlecode.com/svn/trunk@1370 f8528748-c2c0-11dd-ba5c-d3b7c2b3b534