docker: Pylint and pep8 fixes

no code changes, just style updates.

Signed-off-by: Lukáš Doktor <ldoktor@redhat.com>
docker: Add .travis.yml file fo Travis CI

This file configures the Travis CI to check pylint, pep8 and run all
unittests for each pull request/push

Signed-off-by: Lukáš Doktor <ldoktor@redhat.com>