Commiting additional test data files.

* docker_images2.txt - a secondary set of images that includes
  non-redis images.
* docker_images2_no_trunc.txt - a not-truncated version of
  docker_images2.txt. This is for complete image ids to be pared with
  container ids in docker ps.
* docker_ps.txt - Output from `docker ps` of mutliple containers in
  various states: running, stopped, with ports, without ports.
* docker_ps_images2_map.py - Python file that sets up a dict mapping
  container ids to non-truncated image ids.
Add tests to cover 'docker ps -a' cases.

Tests should cover testing skipping running or stopped container images.

Bug found while working on tests, didn't consider that a container can
have no ports set up and that results in an empty column in `docker ps`.
Merge pull request #11 from vky/add-skip-container-tests

Add skip-container tests.