Fix string so gettext script picks it up.
Do not use extract() function.
Better phpDoc for the bp_follow_get_add_follow_button() function.
Organize functions in bp-follow-notifications.php into sections.
Moves some hardcoded notification actions into hookable actions.

See #24.
When adding a notification, add the leader ID as 'secondary_item_id'.

This will allow us to better format the notification when rendered.

This is actually an oversight in BuddyPress as when notifications
are formatted, the 'user_id' parameter isn't passed.  This is really
a workaround.

See #24.
Revert "When adding a notification, add the leader ID as 'secondary_item_id'."

This reverts commit 032b00618db92f713b5e7341cbd1fc4c82dd2660.
Add support to mark notifications as unread.

This commit changes how notifications are cleared.

Previously, follow notifications were redirected to the logged-in
user's followers page and deleted immediately.  Now, follow
notifications are redirected to the follower's profile and
marked as read.

For the bulk follow notification ("X users are now
following you"), the logged-in user is now redirected to the
notifications unread page and not marked as read or deleted.  This
allows the logged-in user to view their follower notifications in the
date that they were followed.

Fixes #24.