Add tarfile from python 2.7.2

This allow method add in Tarfile to have filter parameter.
This give us filter capa on file to include.
Should be removed when python 2.7 will be the minimum version

Because we roolback to python 2.6 requirment, we need to ship.

Overide real chown method from tarfile which make crazy check about
uid/gid before chowning. This leads to bug when a uid/gid doesn't
exitsts on the running system

This overide as a sexy side effect which allow badly create tarball
(whithout --numeric-owner) to be extracted correctly

Concept of data was changed to payload.
Payload is not necessary a tarball of a file or a directory, but, directly a file without tarball around.
This is useful have the same md5 on data/payload and win some space during repo adding.
Now data which come with image are represented by class Payload and all operation are located inside. This is cleaner!
Payload also handle orginial information (mtime,uid,gid,md5,size,mode)

This allow method add in Tarfile to have filter parameter.
This give us filter capa on file to include.
Should be removed when python 2.7 will be the minimum version