This patch review how scripts are executed and modules loaded.

sys.module is preserved from modification by scripts and avoid conflict with
module loaded by scripts

Only support pure python module in lib/, package (like foo.bar) don't work.

Signed-off-by: Sébastien Luttringer <sebastien.luttringer@smartjog.com>

ISException is an Installsystems exception which can handle an exception and
his information (type, value, traceback).

Signed-off-by: Sébastien Luttringer <sebastien.luttringer@smartjog.com>

Ssh connection with agent fail when agent is not able to auth and claims "No Session"
instead of using provided password.

[1] http://stackoverflow.com/questions/6832248/paramiko-no-existing-session-exception
[2] https://github.com/paramiko/paramiko/issues/126

With the permission of Romain Degez, CTO of Smartjog and Sébastien Luttringer.

Signed-off-by: Sébastien Luttringer <sebastien.luttringer@smartjog.com>

Signed-off-by: Sébastien Luttringer <sebastien.luttringer@smartjog.com>

We use current locale to convert argv to unicode and handle it as uncode after.

If we have to format (aka interpolatation) we need to be sure this have to be
done in unicode and not in ascii. This avoid unicode error with ascii string
encoded in utf-8.

Example of failure between a string and an object

b = Exception(u"é")
Exception("error: %s" % b)
 => Exception("error: %s" % str(b)
 => UnicodeEncodeError: 'ascii' codec can't encode character u'\xe9' in position 0: ordinal not in range(128)

This function walk across a directory, for every template which match the
extension, remplace by the rendered file with the same mode/uid/gid as the
template file.
Use jinja2 as template engine.

Signed-off-by: Sébastien Luttringer <sebastien.luttringer@smartjog.com>

Signed-off-by: Sébastien Luttringer <sebastien.luttringer@smartjog.com>

Before this, timeout only apply to repository caching.

Now timeout is used by all transfert functions.
A new parameter repo_timeout is available to set a custom timeout on repository

We now use system tar and gzip to compress/decompress payloads

Goals are:
- Speed-up extraction and creation of payloads.
- Allow to use non-python supported compressor like (pbzip2 and xz)
- Remove python2.7.1 tarfile.py module
- Remove python 2.7.1 gzip.py to avoid filename to be in gzip headers
- Remove gzipstream.py module used to stream gzip file

we need python-progressbar >= 2.3 to work with is.
We previously ship inside it because debian doesn't have 2.3 package available.
now we have built a debian package, we can remove code and add a dependency

old command line option are still present but no more in config file
this allow to override easily on command line config parameters

prepare and uprepare chroot functions now track non existant files
preparing are now done more carrefully about tricks

Image are not crawled anymore in all repositories by default
You needs to specify a list of repo to look in

* tricks /etc/mtab
* new output

this already more easy unchrooting after failure by chrooting again,
solving issue and exiting (which remove mounts again)

chroot failed when root is missing dirs before resolv.conf fil

This is done to be able to use preparation from scripts

this command is and helper to chroot inside payload mounting /{proc,sys,dev,dev/pts} fs
inside the chroot and disable daemon restart