Pick up last few weeks of edX changes up to (and including) last week's
hotfix.

Conflicts:
	common/djangoapps/student/models.py
	common/djangoapps/student/views.py
	common/lib/xmodule/xmodule/capa_base.py
	common/lib/xmodule/xmodule/tabs.py
	docs/en_us/developers/source/xblocks.rst
	lms/djangoapps/certificates/views.py
	lms/djangoapps/courseware/views.py
	lms/envs/common.py
	lms/templates/courseware/course_about.html
	lms/templates/courseware/course_navigation.html
	lms/templates/instructor/instructor_dashboard_2/metrics.html
	lms/templates/problem.html
	lms/templates/register.html
	requirements/edx/github.txt