Feature: cidr tables now support if/endif and negation (by
prepending "!" to a pattern), just like regexp and pcre
tables. The primarily purpose is to improve readability of
complex tables. Files: util/cidr_match.[hc], util/dict_cidr.c,
proto/cidr_table.

Cleanup: make regexp: and pcre: parser warning messages more
similar.  Files: dict_regexp.c, dict_pcre.c.