Porting patch-o-matic-ng to 2.6.11

Rusty's recent changes to the conntrack/nat helper API in 2.6.11-rcX have rendered all conntrack/nat helpers in pom-ng unusable.

I've created a new svn 2.6.11 pom-ng branch and started porting of all the helpers in there. The opportunity was also good to port all the 2.4.x only helpers to 2.6.x, so we won't have the big gap between 2.4.x and 2.6.x supported helpers.

I expect this to take a couple of days, and even after that, for most protocols I have no opportunity to test (proprietary protocols, proprietary software, ...), so I'll have to rely on your feedback.