On the 'moves-tracking-2' branch: define path-based addressing for
the editor in such a way that it can cope with moves.

* subversion/include/private/svn_editor3.h
  (svn_editor3_t and all related declarations): Add a discussion of
    addressing modes. Change path-based addressing to include both
    a peg location and a created-relpath.

* subversion/libsvn_delta/editor3.c
  Adjust accordingly.

git-svn-id: https://svn.apache.org/repos/asf/subversion/branches/move-tracking-2@1607142 13f79535-47bb-0310-9956-ffa450edef68