Switch item.protocol type from string to list
Add item.syn option to dport_limit rule

item.syn allows you to enable packet matching by SYN or !SYN flags.
Update item.{disabled,enabled} logic

This makes enable/disable logic usable with both normal boolean
variables and "boolean" variables passed as strings from other vars.

'dport_limit' got its own version of 'item.enabled' to bring it in line
with 'dport_accept'.
Merge pull request #5 from drybjed/ferm-update

Ferm updates