Changes course_membership checking decorator to redirect to login page

with redirect to originally intended page after login (closes #1883)
Shib support for this login redirect decorate
use view that does SSL upgrade/downgrade
Show selected tab on report reload
a better way to do SSL upgrade/downgrade
Fixed zebra-light color to match surrounding light bg color
Make shib login case more robust

Handle shib failure case to remove redirect loop
Lessen confusing messaging
default redirect to referer
bugfix: message.message
remove text-rendering css attribute to clean up titles and speed up performance
style changes to radio buttons
Merge pull request #2221 from Stanford-Online/jbau-1883-login-redirect

Jbau 1883 login redirect
StudentExamStart in Django Admin

Searchable by student's username
Merge pull request #2230 from Stanford-Online/jbau-studentexamstart-admin

StudentExamStart in Django Admin
remember state in join button
Merge pull request #2228 from Stanford-Online/giulio-retinize-2155

Fix Zebra-light color and remove text-rendering css property and restyle radios and checkboxes
Merge pull request #2241 from Stanford-Online/jbau-1883-login-redirect

remember state in join button
Merge branch 'master' of https://github.com/Stanford-Online/class2go into giulio-reports-reload-2134
Work for #2129 - Drill down to assessment summary report from quizzes
summary in-line report.
rewrote if logic to be positive