Fix various warnings/errors detected by PyLint

[JeremyRand]

One of the fixes was in platform-dependent code, someone please test to make sure it still boots without exceptions on Windows.

[phelixbtc]

Why do you suggest to convert all the option dicts to lists?

[JeremyRand]

@phelixbtc Khal's code was converting dicts to lists at run time (but also accepted lists verbatim); that makes it impossible for PyLint to do static analysis of that code to check for errors.

[phelixbtc]

FTFY: https://github.com/namecoin/nmcontrol/pull/83

[JeremyRand]

Now that #83 is merged, I'll rebase this soon to not include that particular fix.