Search: initialization with db_extend is no longer needed... hopefully

Signed-off-by: Norv <a.w.norv@gmail.com>
Oops. Update files and class->interface.

Signed-off-by: Norv <a.w.norv@gmail.com>
Small documentation/comments updates.

Signed-off-by: Norv <a.w.norv@gmail.com>