Validate firewall rule advanced options requirements (2.1 branch)

Checks that the user has selected a TCP Pass rule etc when using the state-related advanced options. Validates as per the checks that are applied in filter.inc when generating the actual pf rules.
Forum discussion: http://forum.pfsense.org/index.php/topic,64653.15.html
Bug report #3098
This is the version for the 2.1 branch, which is the code I have tested on a real system.