On the fsfs-format7 branch:  Use an internal data type for representations
in noderev containers.  We simply factor out the uniquifier.  That saves
some memory but mainly allows shared reps to actually use the same array /
dictionary entry. 

* subversion/libsvn_fs_fs/noderevs.c
  (binary_representation_t,
   shared_representation_t): new data types to replace representation_t
  (binary_noderev_t): use shared presentation for data reps only
  (svn_fs_fs__noderevs_t): update docstrings only
  (svn_fs_fs__noderevs_create,
   store_id,
   store_representation,
   svn_fs_fs__noderevs_add,
   svn_fs_fs__noderevs_estimate_size,
   get_representation,
   svn_fs_fs__noderevs_get,
   create_rep_stream,
   write_reps,
   svn_fs_fs__write_noderevs_container,
   read_reps,
   svn_fs_fs__read_noderevs_container): update

git-svn-id: https://svn.apache.org/repos/asf/subversion/branches/fsfs-format7@1469497 13f79535-47bb-0310-9956-ffa450edef68