First draft done.

Fixed watch dog receiving the signal to stop too early. It is now stopped after all threads have completed.

Fixed unhomogeneous error names.

Propagated references to the watchdog to disk and tape threads and tasks.
Added a maps for storing the count of all errors that occured during the session.
Added propagation of the counts to the initial process.
Added error reporting in disk and tapes threads and tasks by using a string marker
allowing to know which part went wrong in high level exception. Exceptions then
bumps up the count in the watchdog (synchronously), and the watchdog sends the
new count to the initial thread later (in the watchdog's thread).
Plus some missing logs fixed when an exception is thrown in a disk write task.

Added interface to reference the recall watchdog to the recall disk thread pool.
Next: Do same for migration. Actually store the reference. Add new error map storing in watchdog. Add error reporting in tape and disk threads.

WIP: Added missing file ID for disk write thread. Added missing error log when an exception is thrown in a disk write task.

WIP: switching to CASTOR-4839 tapeserverd: task injector should decide on closing the session earlier

WIP. Next: log unmount errors (in the RAII)

Finished error counting in data threads.

Enabled skipping the Cupv check if the user asking for the privilege is the same as the one running the daemon

Added a the new criteria (less that half the work asked for) for ending the session for migrations.
The symetric for recalls is not possible currently as we do not know the file size beforehand in recalls (it is found out from data on tape).

Renamed runningtransfersset.remove() into kill() and introduced a real remove() method without side effects, that is used in two places

Remove transfers from the runningtransfers set as soon as possible, i.e. when the mover calls close()

Added the possibility of specifying the ceph userId in the ceph library and used it in the CASTOR code

Fixed.