- In --Obfuscate-filenames mode, added support for also obfuscating

- In --Obfuscate-filenames mode, added support for also obfuscating
directories.  Each directory is obfuscated similarly to files, so
/some/directory/path/ becomes /some/directory/gpgdir_dN where "N" is
an integer that is incremented for each directory at the same relative
path level.  The original directory names are stored in an encrypted
file ".gpgdir_dir_map_file.gpg" for each original directory.  The top
level directory path is not obfuscated.
- Better pid file handling so that the <dir>/.gpgdir.pid file is removed
at gpgdir shutdown even if various error conditions exist.
- (Test suite): Added more rigorous test suite support for ensuring that
the shape of a directory is preserved across the encrypt/decrypt cycle.
There was already code to verify MD5 sums across the cycle, but now an
error will be thrown if any file is lost or a new file is created by
gpgdir inappropriately.

git-svn-id: file:///home/mbr/svn/gpgdir_repos/gpgdir/trunk@352 958e171a-1414-0410-8e2f-9d295d3c0db0