Rename existing mailing list stuff

Since we're not really giving people the ability to "opt in" on this, it
seemed confusing to leave the code structured like that. Now we can just
check if they have not opted out to determine if we can send mail.
Add ability to send mailing list type messages
Add unsubscribe link
Add message about unsubscribing
Commit for testing mailing list
Mailing list tweaks
Update email templates to better handle html
Change copy for user facing mailing list stuff
Remove test email data - We'll do it live!
Update unsubscribe info message
Merge branch 'master' into mailing-list

Conflicts:
	urls.py
Refactor unsub info message
honor translations for module names in subcase ui
remove imports
allow fully qualified custom domain mapping modules
Merge pull request #811 from dimagi/cleanup

remove imports
Merge pull request #810 from dimagi/qualified-reports

allow fully qualified custom domain mapping modules
update ptop and touchforms
Merge pull request #808 from dimagi/subcase-ui-trans

honor translations for module names in subcase ui
Fix ivr report for deleted forms