If extlinux is installed on the root partition (the OS does not have a
separate /boot partition) it needs to be reinstalled, otherwise the OS
won't boot.

As the documentation of libguestfs states, a separated thread should
be started after mount_local has finished and before mount_local_run,
which is a blocking command, gets started. Till now, we used to start
the thread just before mount_local.

Workaround the bug that libguestfs may raise a RuntimeError even if the
command runs successfully, due to the fact that the command exited with
non-zero exit status.

Make sure that the libguestfs appliance is always launched directly
using qemu. This can be done by exporting the environment variable
LIBGUESTFS_BACKEND=direct before importing the guestfs library.

This fixes #38

The base class is named Output. Having a method with the same makes
the code confusing.

Only use the mount feature in the Image class if it is supported by
the libguestfs build. The feature of mounting an image locally through
FUSE was added in libguestfs 1.18.

Mount the image on the host system using FUSE and libguestfs.

The SORTORDER is computed like this: ODDHHLL
O: OS type
D: Distribution
H: Version high
L: Version low

This is automatically assigned according to the OS type and the
distribution of the image.

This resolves #9

When working with the dialog-based version of the program and a fatal
error occurs, create a temporary log file and put the full output of the
program there. This makes it easier for the user to determine what went
wrong.

If qemu-nbd is not present at the host system, only accept raw images
as input media. This is a workaround for ancient systems like CentOS 6.x
where the nbd module is not compiled in the default kernel and the qemu
package does not include the qemu-nbd executable.

This complies better with the python conventions

Only use the device mapper when snapshotting block devices. If the
input media is a regular file, then create a qcow2 image and define
the original media as backing_file.

Use qemu-nbd to export a QEMU image as raw where needed

This used to be a class in the util module, but since this is only used
on the Image, it suits better there.

Don't treat shrink as a seperated task. Add it in the syspreps menu.

Fix a bug that affects newer versions of libguestfs where the handler
is erroneously closed in disable_guestfs

Make sure the guestfs handler is never cached in registry class. There
are cases where the guestfs handler is recreated in image class. The
registry code should always access the guestfs handler from the image
class and never from a local copy.

Use the @property decorator instead of the property() method to create a
read-only os attribute in Image class.

pep8 1.5 introduced a new test (E265) to ensure there's at least one
space before block comment.

According to the decision of the GRNET Board of Directors,
switch license to GPLv3.

This commit will be propagated to the release
and master branches based on git flow, and the next
release will be licensed as GPLv3.

If launching the guestfs helper VM fails, the library will throw a
RuntimeError exception. Don't treat this as an unhandled exception.
Convert it to FatalError but preserve the error message.

This can be used to perform various tests to determine if the media
is supported.

Add a new "Unsupported" os_type class. Images that get created from
unsupported media have the EXCLUDE_ALL_TASKS property enabled.

Before shrinking a filesystem use the e2fsck -y if the underlined
guestfs library supports it.

It used to be a function in util module

Before libguestfs 1.18.4 you cannot shutdown the backend and then
relaunch it

The user may define parameters needed by the os_type classes to perform
the system preparation tasks.

A new needed_sysprep_params method is added to os_type.OSBase that
returns a list with parameters that should be defined by the user.

It has never been used. If we need it in the future, we will bring
it back

Those classes may need to access more Image data than the guestfs
handler and the root device name

This function is used to check if a specified libguestfs version is
smaller, greater or equal to the installed one

 * Prefix all private methods with _
 * Write missing docstrings
 * Move all public methods above the private ones
 * Add module docstrings where missing
 * Define source code encodings on all modules