Merge r573831, r589343 from trunk:

Add option to escape backreferences in RewriteRule.
PR 34602  and  PR 39746
Patch by Guenther Gsenger


Update r573831 to avoid duplicating URL-escaping code.
Ref. http://www.mail-archive.com/dev@httpd.apache.org/msg38532.html

Submitted by: niq
Reviewed by: jim


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.2.x@589615 13f79535-47bb-0310-9956-ffa450edef68