logged-out users on public courses get redirected to preview
minor changes
logged-in users that are not course members get preview
Fix for 404 when empty JABBER_DOMAIN set

* Properly handle empty (rather than merely missing) JABBER_DOMAIN
  configuration variable.
merge conflict resolved
Merge branch 'master' of github.com:Stanford-Online/class2go into jrbl-empty-tps-report-domain-fix

Conflicts:
	main/courses/views.py
Remove confusing config from database_example.py

* Having sample chat config in database_example is a little confusing
  for people, so let's just not put it in there until we're sure
  everything works on our setup.
fixed weird share block bounce effect and made show link text more clear
Merge branch 'master' of https://github.com/Stanford-Online/class2go into giulio-share-results
removed hover states, improved click behavior and made link into a button
removed unnecessary jquery
Merge pull request #2427 from Stanford-Online/jrbl-empty-tps-report-domain-fix

Fix for 404 when empty JABBER_DOMAIN set
fix imports to stop 500 in rightnav timedelta (fix #2437)
moved expand/collapse all button to below announcement list
add total to the coursestudentscore model + aggregator code
remove debug print
Merge pull request #2394 from Stanford-Online/jbau-redirect-to-preview

Jbau redirect to preview
fixing merge conflict with master
preventing weird horizontal share textarea resize bug
Merge pull request #2436 from Stanford-Online/giulio-share-results

Fixed share block bounce effect and made "show block" link text more clear