Adding ssh capability to netfilter script

I refactored the module to provide netfilter rules for ssh users. It doesn't handle multiple ssh sessions at all. If a user logs out it will destroy all rules related to his uid. Need to create a wrapper that will be invoked via ForceCommand or another similar mechanism to handle this and build the argument list.

I asked :uberj to provide a cursory review and changed indentation from tabs to spaces based on his suggestion so it added some noise to the diff. Only a little original code remains so I didn't think it was that big of a deal :)