Nanny: adaptation to latest master changes

-    Fixing crash after ifdown (config node has been freed, but config.node not set to NULL)
-    Creation of the workers and config assignment is moved to create policy function.
-    Adaptation (ni_flatten_ifworkers + ni_fsm_pull_in_children) to the latest master changes - hierarchy
-    Couple of problem found with pull#307 fixed (or hidden by disabling not working functions -> TODO)