@classmethod are used in Python to represent methods that can
query and update the class (cls parameter). Is expected to be
used for metaprograming, or advanced techniques that require the
access to the class itself, before we have an instance.
@staticmethod are used to associate a function to a class. It will
not be have access to the instance (self) not the class (cls). In
other programming languages are known as class methods.
This patch replace all the @classmethod with @staticmethod when
there is not need to access to the cls parameter, because the
intention is to be used as normal functions.
In case of a literal decoding failure it tries to decode
the result in utf-8. This is handy in python2 environments where
python and the host might be using different charset configurations.
In python3 this issue seams to be solved.
Fixes#829 and bsc#1110871
