Courseware license (Creative Commons): FED

Use native checkboxes for courseware license options
In Studio settings editor for video module, don't show license if feature-flagged off
Don't let Scope.contents fields leak to Studio editor
JS gettext() must all be on the same line for i18n
Add docstrings for bok-choy tests
Remove LicenseMixin from HTMLDescriptor
Responding to UX review feedback
Add aria-pressed attribute
Use https links instead of protocol-relative links for links to creativecommons.org
Remove license from course outline page in Studio

common/lib/xmodule/xmodule/split_test_module.py

@@ -473,7 +473,8 @@ class SplitTestDescriptor(SplitTestFields, SequenceDescriptor, StudioEditableDes
         non_editable_fields = super(SplitTestDescriptor, self).non_editable_metadata_fields
         non_editable_fields.extend([
             SplitTestDescriptor.due,
-            SplitTestDescriptor.user_partitions
+            SplitTestDescriptor.user_partitions,
+            SplitTestDescriptor.group_id_to_child,
         ])
         return non_editable_fields