Removed the notion of tape density.

objectstore/Tape.cpp

objectstore/Tape.hpp

objectstore/TapePool.cpp

objectstore/TapePool.hpp

objectstore/TapeTest.cpp

objectstore/cta.proto

scheduler/ArchiveMount.cpp

scheduler/ArchiveMount.hpp

scheduler/OStoreDB/OStoreDB.cpp

scheduler/OStoreDB/OStoreDB.hpp

scheduler/OStoreDB/OStoreDBFactory.hpp

scheduler/RetrieveMount.cpp

scheduler/RetrieveMount.hpp

scheduler/Scheduler.cpp

scheduler/Scheduler.hpp

scheduler/SchedulerDatabase.hpp

scheduler/SchedulerDatabaseTest.cpp

scheduler/SchedulerTest.cpp

scheduler/TapeMount.hpp

...ver/castor/tape/tapeserver/daemon/DataTransferSession.cpp