CalledProcessError in python 2.6 doesn't take kwargs

Thanks to https://gist.github.com/edufelipe/1027906
and EduFelipe for pointing out the necessary fixes
Dont use asserts for the library

The python impl. I am using have __debug__ false
Add method to deactivate scheme
Ifup doesn't support options
Always force ifup to reconfigure the interface verbosely
Ignore pyo files
Up interface before scanning for networks