Make some changes to allow compressed property lists in libsvn_fs_fs.
Make some changes to allow compressed property lists in libsvn_fs_fs.

* libsvn_fs_fs/structure:
  Wrap a representation header and trailer around property reps.
  Reorganize the way they are presented so that the term
  "representation" is generic.  Simplify the representation of
  directories and fold the resulting description into the presentation
  of reps.  Change the "rep" field name to "text" in node-revs, since
  "rep" is no longer specific to text reps.

jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion