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?
Should this maybe just be `networks`? Would be more consistent with the way we're naming every other field.