tools/virsh-network.c:
  * vshNetworkSorter to sort networks by name

  * vshNetworkListFree to free the network objects list.

  * vshNetworkListCollect to collect the network objects, trying
    to use new API first, fall back to older APIs if it's not supported.

  * New options --persistent, --transient, --autostart, --no-autostart,
    for net-list, and new field 'Persistent' for its output.

tools/virsh.pod:
  * Add documents for the new options.