On the fsfs-format7 branch:  Use the new noderevs container in packed revs.
Since packing already sorts noderevs roughly by node and path, we simply
need to put them into a common container.  Teach the data access code to
extract the noderevs from the container again.

* subversion/libsvn_fs_fs/index.h
  (SVN_FS_FS__ITEM_TYPE_NODEREVS_CONT): declare new container type id

* subversion/libsvn_fs_fs/pack.c
  (sub_item_ordered_t): define new utility struct
  (compare_sub_items): define associated sorter function
  (compare_p2l_info_rev): switch to decorated objects
  (select_block_entries): new function doing the magic of containerizing
                          noderevs and pulling in as much data as possible
  (copy_items_from_temp): use the new function when copying items
  (write_l2p_index): we can't guarantee sub-items in containers to be ordered
                     by revision anymore -> sort them here

* subversion/libsvn_fs_fs/cached_data.c
  (block_read_noderevs_container): reader for noderev containers
  (block_read): process noderev containers as well


git-svn-id: https://svn.apache.org/repos/asf/subversion/branches/fsfs-format7@1467472 13f79535-47bb-0310-9956-ffa450edef68