Prevent XSS attack via submission_history page.

Conflicts:
	lms/djangoapps/courseware/tests/test_views.py
Studio: revises spacing fix for welcome to edX studio title

Conflicts:
	cms/templates/howitworks.html
Merge pull request #482 from edx/hotfix-2013-07-23

Hotfix 2013 07 23
Merge branch 'release'

Conflicts:
	lms/djangoapps/courseware/tests/test_views.py