Add pylint

[drts01]

• pylint import-error bug workaround for distutils
• pylint unidiomatic-typecheck
• pylint len-as-condition
• pylint old-style-class
• add pylintrc and to tox

I disabled some failing tests for now, but at least there will be some test coverage w/ pylint.

[andsens]

Sorry for the delay. Vacation and stuff :-) Looks great! I'm merging this!