The constructor and the accessor have been changed accordingly

TryMutexLocker will try to lock the according mutex. To know if it succeededm it is implicitly convertible to bool (true meaning mutex locked, false not locked)

The circulation of the blocks in case of error is now done according to the number of mem blocks initially needed to transfer the whole file

Fixed stupid new line at the end of the file for SLC5 in DiskReadThreadPool.cpp and DiskWriteTask.cpp

m_failled->m_failed, capacity -> totalCapacity

Conflicts:
	castor/tape/tapeserver/daemon/DiskReadTask.hpp
	castor/tape/tapeserver/daemon/DiskWriteTask.hpp
	castor/tape/tapeserver/daemon/MemBlock.hpp

The new functionnality allows reading of tape blocks into the MemBlock. The size
of the tape blocks is managed here.

Only affects the debuf version with file and line numbers.

The exceptions are now SErrnum instead of Errnum (because rfio sets serrno and not errno. Also the destructor cantno longer let an exception escape

The upcoming modofication will change the tape file interface, switching from the ad-hoc Fileinfo structure
to just using the structure from the network messages directly. We will not update those little used test programs.

This will impact the unit tests and make them more talking, showing
the logs as they come. We might want to make this behavior optional
in the long run (to limit the logs in the automatic builds).

Fixed comment: the default serrno for castor::exception::Exception(std::string) is SEINTERNAL, not  0.