Merge pull request #7974 from edx/merge-release-to-master

cms/djangoapps/contentstore/views/preview.py

common/lib/xmodule/xmodule/modulestore/tests/django_utils.py

common/lib/xmodule/xmodule/modulestore/xml.py

common/lib/xmodule/xmodule/tests/__init__.py

common/lib/xmodule/xmodule/tests/test_import.py

common/lib/xmodule/xmodule/tests/test_library_content.py

common/lib/xmodule/xmodule/tests/test_split_test_module.py

common/lib/xmodule/xmodule/x_module.py

common/test/acceptance/tests/video/test_video_times.py

lms/djangoapps/courseware/module_render.py

lms/djangoapps/courseware/tests/test_module_render.py