TransRead: add pbzip2 support

TransRead: add pbzip2 support

This patch adds support for multi-stream bz2 files (creted with pbzip2).
Unfortunately, the standard python 2.7 'bz2' module does not support it, so we
use the 'bz2file' module from PyPI.

'bz2file' may not be present in the system, in which case we fall-back to the
standard python 2.7 'bz2' module. As a bonus, 'bz2file' is a little bit faster
than 'bz2' even for single-stream archives.

Change-Id: I7b473987a3bda0241f49da5bbdf1a8a2b3841400
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@intel.com>