Add mknmz-wwwoffle, a tool which performs full-text search over the cache created by
WWWOFFLE, using full-text search system Namazu (http://www.namazu.org/). mknmz-wwwoffle
adds a filter for mknmz which is used to generate index files for cache entries in WWWOFFLE.

PR: ports/66168
Submitted by: Andrey Slusar <vasallia@ukr.net>