The invite function may not applicable for private and/or closed installs. This adds a configuration option to enable/disable invites (defaulting to enabled), hides the "Invite" nav item when necessary, and adds a check to actions/invite.php.
Note that I haven't tried the Facebook application so I didn't add any checks to actions/facebookinvite.php.
- Added Facebook Connect tab to login nav
- Show Facebook mini-avatar when logged in
- Added Facebook Connect tab to connect settings nav
- Option to disconnect from Facebook