Refactor.
* gettext-tools/src/read-catalog-special.h (parse_comment_special): Renamed from
po_parse_comment_special.
* gettext-tools/src/read-catalog-special.c (parse_comment_special): Renamed from
po_parse_comment_special.
* gettext-tools/src/read-catalog.c (default_comment_special): Update.
* gettext-tools/src/xg-message.c (remember_a_message): Update.
* gettext-tools/src/x-ruby.c (extract_ruby): Update.
* gettext-tools/src/xgettext.c (xgettext_record_flag): Update comment.
