Revision 1806619

On the 'shelve' branch: Let 'unshelve' default to the most recent shelved
change.

* subversion/svn/svn.c
  (svn_cl__cmd_table): Show NAME argument as optional.

* subversion/svn/shelve-cmd.c
  (list_sorted_by_date): New, factored out of shelves_list().
  (name_of_youngest): New.
  (svn_cl__unshelve): Default to the most recent shelved change.