On the authzperf branch:  Implement support for generic / complex
wildcard patterns like "/foo*bar*baz/".

To do this efficiently requires normalized pattern paths, so we
add the normalization logic as described here:
https://wiki.apache.org/subversion/AuthzImprovements

* BRANCH-README
  (TODO, DONE): The last pattern TODO is now DONE.

* subversion/include/svn_string.h
  (svn_stringbuf_replace_all): Declare another stringbuf API function.

* subversion/libsvn_subr/string.c
  (svn_stringbuf_replace_all): Implement it.

* subversion/libsvn_repos/authz.c
  (node_pattern_t): Add a container of all odd / complex patterns.
                    No specific ordering on this one.
  (insert_path): Finally add the "catch-all-other" case.
  (normalize_wildcards): New pattern path normalization code.
  (process_path_rule): Ensure properly normalized patterns.
  (finalize_tree): Cover yet another set of sub-nodes.
  (match_to_next_wildcard,
   match_pattern,
   add_complex_matches): New generic pattern matching logic.
  (lookup): Handle yet another class of patterns.

git-svn-id: https://svn.apache.org/repos/asf/subversion/branches/authzperf@1614703 13f79535-47bb-0310-9956-ffa450edef68