First part of some serious refactoring

The problem is that teh convergence model does not works as it currently is
Firewall rules will get added but not deleted

This builds a table of firewall rules that need to be present
The new CsNetfilter class will then do:
1.  Add rules that are not present
2.  Delete any that were not explicitly in the add list

WIP
Merge branch 'feature/systemvm-persistent-config' of github.com:schubergphilis/cloudstack into feature/systemvm-persistent-config