pylint: Fix a large amount of warnings and errors found by pylint

The errors range from indent errors to unused imports.

There's still plenty of things pylint is complaining about but
on pylint's completely bogus scale this improves the score with
pylint 1.1.0 on my machine from 5.37 to 6.79.

While at it, tune .pylintcfg to ignore more issues:
missing method docstring warnings, longer minimum line lengths etc
pylint: Simplify multi-line imports statements a bit

Pylint disliked the repetition among the different files, but a
better reason to simplify this is that these multiline imports
aren't really needed and can be simplified.
pylint: Fix incorrect indentations for pylint 1.2.1

The newer pylint is more strict about indent continuation
being correct. This commit should be purely cosmetic
and not do any code actual code changes.