Docker: Reset minimum autotest version

Formerly, the version set could not be reached from current
HEAD for whatever reason (non-ff update maybe?).  Reset
the minimum default reference to one currently reachable.

Signed-off-by: Chris Evich <cevich@redhat.com>
docker: Pylint and pep8 fixes

no code changes, just style updates.

Signed-off-by: Lukáš Doktor <ldoktor@redhat.com>
Merge pull request #208 from cevich/def_ver

Docker: Reset minimum autotest version
dockertest.images & containers: Only check SubBase

Similar to change made for DockerCmd, to allow instances
implementing the common aspects of Subtest and SubSubtest
to be used interchangably.

Signed-off-by: Chris Evich <cevich@redhat.com>
dockertest.images: Switch to TextTable

Switch to using output.TextTable to parse
docker images output.  This is for consistency
with containers module and to help verify
header-column widths always matches content widths.

Also added ``images_args`` attribute in case
instances need to pass more/different arguments
than just ``--no-trunc``.  Removed a no-longer
relevant FIXME.

Signed-off-by: Chris Evich <cevich@redhat.com>
Merge pull request #193 from cevich/TextTable_images

dockertest.images: Switch to TextTable
Merge branch 'img_cnt_subbase' of https://github.com/cevich/autotest-docker

Conflicts:
	dockertest/images.py
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>
Merge pull request #207 from ldoktor/travis

docker: Support for Travis CI