For now, run using weboob package from PYTHONPATH. Maybe we should
require setup.py to have been run before being able to start run_tests.
This way, we're sure everything is set up.

Same for make_man and weboob_lint.

This is starting to get quite repetitive though.

Always run Python scripts through the same interpreter.
Also simplify the running of pyflakes and flake8, as recent versions all
support execution through python -m. Due do the many variations among
distributions, it makes the whole thing much simpler.

related to e93d724e

Because of BSD.

Laurent Bachelier authored Mar 27, 2012 and Romain Bignon committed Mar 27, 2012

Force using local modules / code.