Add registration module.
Enable registration.
hook_default_registration_type
Add registration field.
Set display settings.
squash all private comment commits #2558

* Renames "Drupal comments" to "Private comments"
* Only site members can add and view private comments
* Removes the "Log in to post comments" link
* Adds link to App Settings on node form comment settings
* Update behat tests
Add og_tasks proof of concept
Merge branch 'SCHOLAR-3.x' into 2913
Start cleanup.
#2871: Set access resource file permission on install and update.
Fix typo
update robotstxt variable to hide other vsites files dirs #2797

#### Changes
* every vsite now has directives-- either disallow all (private), or
disallow other sites' files dirs (public).
* rename php vars to match variable names
* refactor to reduce identical logic checks
* comments
Fix bugs encountered while running tasks via site/register
add update hook to add og_tasks
Add initial tasks.
account for shared domains and ksort directives array #2797
refactor & update comments #2797
Add relationship correctly.
Add test.
Apply the correct path for ER.