Add initial .pep8 configuration file

Max line length is set to 256 - this is too long, but there are
*a lot* of scripts with very long lines. This allows us to fix the
most important ones first.

distribute_setup.py is externally-delivered and is thus ignored
externals/* should be ignored
user-config.py also should be ignored

all i18n files and date.py are basically databases-in-python-format
and therefore are exempt from pep8 rules

Change-Id: I1bba208a9277dbcacb0e2c2001e2dc3252e4b21b
pep8-ified generate_user_files.py

Change-Id: I88421c42e64e3176fc77ab9f60fcaac31bac8ac4
Merge changes I88421c42,I1bba208a

* changes:
  pep8-ified generate_user_files.py
  Add initial .pep8 configuration file