Api network put delete

I have one big question mark in this pull request: the Vlan model (now the Network model) took a parameter 'nic_id', which isn't in the API anywhere, so I don't know what it's supposed to do.  I currently set it to the value 'FIXME', which is clearly dumb, so please do not merge this yet.  What should this do?
We actually us _list for the backreference for groups consistently---this dates back to me trying to use a decorator to make these automatically, and failing miserably.  (Note that _list can be added trivially, while pluralizing English nouns is hard.)