Storage refactoring. Posix file functions now differentiate between open and missing errors. Don't use negations in objects below Storage. Rename posix driver files/functions for consistency. Full abstraction of storage driver interface. Merge protocol storage helper into storage helper.
+Storage refactoring. Posix file functions now differentiate between open and missing errors. Don't use negations in objects below Storage. Rename posix driver files/functions for consistency. Full abstraction of storage driver interface. Merge protocol storage helper into storage helper. Add CIFS driver to storage helper for read-only repositories.