app: Micro coding-style fix
vm-creator: A bit more debug

Add a bit more debug around storage pool/volume creation code.
vm-creator: Refactor config creation code

Put config creation code into a separate method: create_domain_config.
We keep it protected and virtual cause in a later patch we'll override
this from a new subclass.
vm-creator: Refactor create_domain_name_and_title_from_media

Seperate out creation of base name and title to seperate virtual
protected method so subclasses can provide their own implementation for
this.
installed-media: Rename 'convert_to_native_format'

Rename 'convert_to_native_format' method to just 'copy'. The conversion
part is internal detail.
installed-media: Provide a sync constructor as well

This is mainly needed as workaround for bug#712186 when we subclass
InstalledMedia in a following patch in this series.
vm-importer: Allow subclasses to not start VM after import
Introducing libvirt system importing classes

a. LibvirtSystemMedia: Represents main disks of system libvirt domains.
b. LibvirtSystemVMImporter: A subclass of VMImporter that will be
   responsible for importing a VM from system libvirt.
Allow user to import system libvirt VMs

On launch of Boxes, if there is no boxes defined and there is VMs
available on system libvirt, allow user to import those VMs to session
libvirt (and therefore Boxes).

We gotta elevate privileges to change permissions on disks/images as by
default they are not even readable to anyone but root/qemu. This
unfortunately means launching of undesirable polkit dialog.
vm-configurator: Add setup_custom_xml()

Add a public method to setup custom XML on new domains. We'll use this
for domains imported from system libvirt, where most of the config is
mostly copied from an existing domain. Therefore create_domain_config()
is not used and that means update_custom_xml is never called either.
Restore system libvirt imports from previous runs

Save the state for system libvirt imports so that if Boxes is quite
before import is finished, the import is restarted next time Boxes is
run.