Allow veryisolated networks without IP
Allow veryisolated networks without IP

* Moved network lookup by IP to `lookup_network_by_ip`
* Lookup by name only if lookup by ip fails *and* forward_mode is
  `veryisolated`. This will preserve existing functionality.
* Added network creation ability to `handle_network_name_option`
** Network **must** be veryisolated to be created by name
** Network **must not** have an ip address to be used in the
   `handle_network_name_option` path.

Minor changes:
* corrected inverted autostart logic
* screen formatting

Fixes #402

mandre/vagrant-libvirt,timhughes/vagrant-libvirt,Paulche/vagrant-libvirt,freexploit/vagrant-libvirt,electrofelix/vagrant-libvirt,pradels/vagrant-libvirt,tkrille/vagrant-libvirt,skamithi/vagrant-libvirt,pronix/vagrant-libvirt,swizzley/vagrant-libvirt,gbriones1/vagrant-libvirt,d0c-s4vage/vagrant-libvirt,brk3/vagrant-libvirt,tkrille/vagrant-libvirt,electrofelix/vagrant-libvirt,leoh0/vagrant-libvirt,skamithi/vagrant-libvirt,dustymabe/vagrant-libvirt,vagrant-libvirt/vagrant-libvirt,gbriones1/vagrant-libvirt,freexploit/vagrant-libvirt,moozer/vagrant-libvirt,vagrant-libvirt/vagrant-libvirt,volago/vagrant-libvirt,electrofelix/vagrant-libvirt,joejulian/vagrant-libvirt,sendgrid-ops/vagrant-libvirt,d0c-s4vage/vagrant-libvirt,pronix/vagrant-libvirt,joejulian/vagrant-libvirt,mandre/vagrant-libvirt,pradels/vagrant-libvirt,bexelbie/vagrant-libvirt,infernix/vagrant-libvirt,infernix/vagrant-libvirt,vagrant-libvirt/vagrant-libvirt,leoh0/vagrant-libvirt,timhughes/vagrant-libvirt,dustymabe/vagrant-libvirt,brk3/vagrant-libvirt,Paulche/vagrant-libvirt,bexelbie/vagrant-libvirt,moozer/vagrant-libvirt,infernix/vagrant-libvirt,sendgrid-ops/vagrant-libvirt,swizzley/vagrant-libvirt,volago/vagrant-libvirt