og 5.x-6.0-rc4

Changes since DRUPAL-5--6-0-RC3:

• #240884. restrict access to og panels pages like we do for the group itself.
• unfortunate hack to set tab title in og_panels
• #240895 by Lynn. Modified by Moshe Weitzman. Bad syntax when groups appear on registration form.
• #241814. Allow members to see the subscription form for a private group (if group has open or moderated membership request handling).
• #241603 - smarter destination when joining a group. also misc comment cleanup.
• #241027 by v1nce. modified by moshe weitzman. smarter destination after an unsubscribe.
• do not disable page title in og_panels page form
• Add 'group faces' content item for usage in panels