Shorted names contaning the word Directory by replacing it with Dir

Doxyfile

middletier/CMakeLists.txt

middletier/cta/DirEntry.cpp

middletier/cta/DirEntry.hpp

middletier/cta/DirIterator.cpp

middletier/cta/DirIterator.hpp

middletier/cta/FileSystemDirEntry.cpp

middletier/cta/FileSystemDirEntry.hpp

middletier/cta/FileSystemNode.cpp

middletier/cta/FileSystemNode.hpp

middletier/cta/MiddleTierAdmin.hpp

middletier/cta/MiddleTierUser.hpp

middletier/cta/SqliteMiddleTierAdminTest.cpp

middletier/cta/SqliteMiddleTierUser.cpp

middletier/cta/SqliteMiddleTierUser.hpp

middletier/cta/SqliteMiddleTierUserTest.cpp

middletier/cta/Vfs.cpp

middletier/cta/Vfs.hpp

middletier/cta/VfsTest.cpp

xroot_plugins/XrdProDir.cpp