On the fsfs-format7 branch:  Make the textual representations (noderevs
and change lists) in FSX handle control chars.  The binary container
representations don't have this problem and as soon as we eliminate the
textual representations, this escapement will no longer be necessary.

* subversion/libsvn_fs_x/low_level.c
  (auto_escape_path,
   auto_unescape_path): new utility methods for escaping paths
  (svn_fs_x__read_noderev,
   svn_fs_x__write_noderev,
   read_change,
   write_change_entry): 

* subversion/libsvn_fs_x/tree.c
  (check_newline): drop
  (x_make_dir,
   x_copy,
   x_make_file): no longer check for newlines in path parameters

git-svn-id: https://svn.apache.org/repos/asf/subversion/branches/fsfs-format7@1507728 13f79535-47bb-0310-9956-ffa450edef68