Unified command execution in Docker containers.

Also adds a hotfix for a broken test execution based on
an issue with a used library: https://github.com/pytest-dev/pytest/issues/4770

Change-Id: I54aade1eda31cb2584641b95226fbf39d9d298f4
Signed-off-by: peusterm <manuel.peuster@uni-paderborn.de>
diff --git a/setup.py b/setup.py
index 7cc9d6b..7fb1add 100755
--- a/setup.py
+++ b/setup.py
@@ -57,7 +57,9 @@
           'ipaddress',
           'simplejson',
           'gevent',
-          'flake8'
+          'flake8',
+          # fixes: https://github.com/pytest-dev/pytest/issues/4770
+          'more-itertools<=5.0.0'
       ],
       zip_safe=False,
       entry_points={
@@ -66,5 +68,5 @@
           ],
       },
       setup_requires=['pytest-runner'],
-      tests_require=['pytest'],
+      tests_require=['pytest', 'more-itertools<=5.0.0'],
       )