Inclusing xattr as dependency to install crefi.

Signed-off-by: Vijaykumar Koppad <vijaykumar.koppad@gmail.com>
adding version.py in python_modules

Signed-off-by: Vijaykumar Koppad <vijaykumar.koppad@gmail.com>
Changed the description in README.md.

Signed-off-by: Vijaykumar Koppad <vijaykumar.koppad@gmail.com>