fix: incorrect parsing of 'Send to a specific role'

No alerts work, when I select to send to a specific role, such as administrator.

Fix,
change, ':role' to :role,
i.e. change
$result = db_query("SELECT mail FROM {users} AS u INNER JOIN {users_roles} AS r ON u.uid = r.uid WHERE r.rid IN(':role') and u.status = '1' ", array(':role' => $roles));
to
$result = db_query("SELECT mail FROM {users} AS u INNER JOIN {users_roles} AS r ON u.uid = r.uid WHERE r.rid IN(:role) and u.status = '1' ", array(':role' => $roles));

Note, it can help to add:
watchdog('user_register_notify', 'email to=' . check_plain($to));
after:
$to = implode(', ', $emails);
to actually see in the logs who emails are sent to.