Add :use_rule_comments option

Hi, small change to allow comments to be appended to rules,
makes the output of iptables -L ... easier to grok with lots of nodes/rules.

If set, iptables commands have -m comment --comment "Rule Name Here"
added, resulting in iptables -L output like this:

ACCEPT tcp -- 10.1.2.3 anywhere tcp dpt:http ctstate NEW /* Allow all HTTP */