* fix type mismatch in third_party_auth migrations
* fix type mismatch in verify_student migrations
* fix type mismatch in video_config migrations
* fix type mismatch in verified_track_content migrations
* fix type mismatch in commercemigrations
* fix type mismatch in xblock_config migrations
* fix type mismatch in course_creators migrations
* fix type mismatch in contentstore migrations
* INCR-244: Make compatible with Python 3.x without breaking Python 2.7 support on common/test/acceptance/pages [common, xblock]
* INCR-244: Add missing module docstring and fix for six import
* INCR-244: Update module docstring
Change expectedFailure decorators to skip, because that still takes
a screenshot as if it were an error and at least one of those
take a super long time when running locally on devstack.
This requires fixing the javascript api implementation, and adding
an implementation of get_block to the ModuleSystem api.
However, the implementation is incomplete, due to mismatches between
the expectations of XModule and XBlock.
Also adds tests using the Acid block to make sure that the javascript
and python apis for children are working correctly.