Merge pull request #1558 from edx/sarina/beta_email_background_history

lms/djangoapps/instructor/tests/test_api.py

lms/djangoapps/instructor/views/api.py

lms/djangoapps/instructor/views/api_urls.py

lms/djangoapps/instructor/views/instructor_dashboard.py

lms/envs/common.py

lms/static/coffee/src/instructor_dashboard/send_email.coffee

lms/static/coffee/src/instructor_dashboard/util.coffee

lms/static/sass/course/instructor/_instructor_2.scss

...mplates/instructor/instructor_dashboard_2/send_email.html