configure-network can now add port-forwarding rules to adapters.

Example: to configure an adapter that port forwards the host's port 8008 to the
guest's port 80:

(configure-network machine {:attachment-type :nat
                            :nat-rules [{:name "http", :protocol :tcp,
                                         :host-ip "", :host-port 8080,
                                         :guest-ip "", :guest-port 80}]})
Merge pull request #47 from briprowe/develop

Add support for NAT port-forwarding rules in network adapters.
Add import of vagrant .box urls to setup-model
Merge branch 'feature/vagrant-box-support' of github.com:tbatchelli/vmfest into feature/vagrant-box-support