Add support for walking externals to the api behind 'svn info', like how this
is implemented for 'svn status'.

* subversion/include/svn_client.h
  (svn_client_info4): New function.
  (svn_client_info3): Deprecate function.

* subversion/include/svn_wc.h
  (svn_wc_notify_action_t): Add svn_wc_notify_info_external value.

* subversion/libsvn_client/deprecated.c
  (svn_client_info3): New function.

* subversion/libsvn_client/info.c
  (includes): Put in understandable order. Add svn_sorts.h.
  (do_external_info): New function.
  (svn_client_info3): Rename to ...
  (svn_client_info4): ... this. Add argument. Handle externals for local info.

* subversion/svn/info-cmd.c
  (svn_cl__info): Update caller.

* subversion/svn/notify.c
  (notify): Add notification for svn_wc_notify_info_external.

* subversion/svn/svn.c
  ("info"): Support opt_include_externals.

Suggested by: schabi


git-svn-id: https://svn.apache.org/repos/asf/subversion/trunk@1550206 13f79535-47bb-0310-9956-ffa450edef68