Make MultiRegexReplaceStringTransformer extend RewriteRule so that it ca...

Make MultiRegexReplaceStringTransformer extend RewriteRule so that it can be used with org.archive.wayback.replay.html.rewrite.RewritingStringTransformer. This will allow applying multiple RegexReplaceStringTransformers for a single oracle policy so many different custom rewrites can be applied to a single url. This will be used by oracleRewriter in AIT Wayback ArchivalUrlReplay.xml.