We need to make sure the coverage of the UT is enough

It now uses interfaces' types (TapeSingleThreadInterface<>, ClientInterface, and DiskThreadPoolInterface<>)instead of the types of the derived classes for its arguments

Thus the RecallTaskInjectorTest.cpp does not complain about link error

Indeed, there was a clash into auto_ptr destructor (which does a delete) and the allocation which was done using new[]

Added explaination for more bare dynamic casts to reference. Also added
cast to void for the result (to prevent compilation errors).

Added explaination for a bare dynamic cast to reference, which is not to
straightforward.

does not compile yet

Also removed the nested Worker class to make the interface inheriting from Thread

and refactor a bit of code into the interface

Fixed missing unsigned type on literal for SLC5.
Removed leftoved from merge
Removed unused class with Clang errors

and the new CASTOR logging facility.