Automatic restore script

[twilligon]

• Refactor single file into module (e1b1519)
• Basic restore functionality (aae2c0e)
• Create non-dummy implementation of DiskLock (see libvirt source, it doesn't look like this stuff is in the Python wrapper)
  • Submit patch to that file to mailing list: s/A lock driver which locks nothing/A lock driver for virtlockd/
  • Add capability to "hotplug" disks out while being restored and back in afterwards (ask user first) (perhaps make a new issue, this isn't necessarily an 0.2 blocker)
• Handle differences between backed up domain & current domain
  • Warn if disk sizes change
    • Logical size (what the VM sees)
      • Interface with qemu-img and similar utils? (see "Valid volume format types" from https://libvirt.org/storage.html, looks like most are supported by qemu-img)
    • Physical size (space on disk)?
  • Attach new disks if explicitly requested (disk removed from domain but later selected for restore)
• Add backup-vm usage to README (6f6f54c)