Extract the mtcc public api to its own header.

* build.conf
  (libsvn_client): Export functions in svn_client_mtcc.h.

* subversion/include/svn_client.h
  (svn_client_mtcc_t,
   svn_client_mtcc_create,
   svn_client_mtcc_add_add_file,
   svn_client_mtcc_add_copy,
   svn_client_mtcc_add_delete,
   svn_client_mtcc_add_mkdir,
   svn_client_mtcc_add_move,
   svn_client_mtcc_add_propset,
   svn_client_mtcc_add_update_file,
   svn_client_mtcc_check_path,
   svn_client_mtcc_commit): Move to svn_client_mtcc.h

* subversion/include/svn_client_mtcc.h
  New header.

* subversion/libsvn_client/mtcc.c
  (includes): Add svn_client_mtcc.h.

* subversion/svnmucc/svnmucc.c
  (includes): Add svn_client_mtcc.h. Remove a few unused headers.

* subversion/tests/libsvn_client/mtcc-test.c
  (SVN_DEPRECATED): Remove unneeded define.
  (includes): Add svn_client_mtcc.h and remove a few unused headers.


git-svn-id: https://svn.apache.org/repos/asf/subversion/trunk@1562052 13f79535-47bb-0310-9956-ffa450edef68