Store ript rules DSL filename + line number on iptables rules

This will allow operators to track down where particular rules came from. 

We can use the [comment module](http://ipset.netfilter.org/iptables.man.html#lbAN) to do this:

```
comment
    Allows you to add comments (up to 256 characters) to any rule.

    --comment comment

    Example:
           iptables -A INPUT -i eth1 -m comment --comment "my local LAN"
```
