Merge branch 'master' into courselecture

Conflicts:
Gemfile
Gemfile.lock
app/assets/javascripts/password_resets.js.coffee
app/assets/javascripts/sessions.js.coffee
app/controllers/lectures_controller.rb
app/helpers/lectures_helper.rb
app/models/lecture.rb
app/models/sm.rb
app/models/user.rb
app/views/courses/show_instructor.html.erb
app/views/courses/show_student.html.erb
app/views/devise/registrations/edit.html.erb
app/views/devise/sessions/new.html.erb
app/views/layouts/application.html.erb
app/views/lectures/edit.html.erb
app/views/lectures/new.html.erb
app/views/lectures/show_instructor.html.erb
app/views/lectures/show_student.html.erb
app/views/shared/_lecture.html.erb
app/views/shared/_sentiment_pill.html.erb
app/views/users/show.html.erb
config/routes.rb
db/schema.rb
db/seeds.rb
test/fixtures/course_enrollments.yml
test/fixtures/lectures.yml
test/fixtures/sentiments.yml
test/models/course_test.rb
test/models/lecture_test.rb