Make the 'svn_client_cat()' API a bit more generic usable for api users,
by allowing the suppression of keyword expansion and by optionally returning
the properties of the node.

* subversion/include/svn_client.h
  (svn_client_cat3): New function.
  (svn_client_cat2): Deprecate function.

* subversion/libsvn_client/cat.c
  (svn_client_cat2): Rename to ...
  (svn_client_cat3): ... this. Add support for not expanding keywords and
    for returning the properties.

* subversion/libsvn_client/deprecated.c
  (svn_client_cat2): New function.


git-svn-id: https://svn.apache.org/repos/asf/subversion/trunk@1544182 13f79535-47bb-0310-9956-ffa450edef68