examples/emptyServer: bugfixes and enhancements

- add option untilfree to give a space makr until
a server should be freed.
- check destination partition for validity
- some beautifications
dao-parsing: use redundant fiedl to get RO-ID

since first cloneID is not always filled.
OSDVolService: DAO now returns objects, not dicts.

Deal with that change
Merge pull request #90 from chanke/master

update to current