Custom block creation

This patch makes its possible to create custom blocks from the install profile.

The following lines were removed from install_add_block(), since i'm pretty sure it would never work.

    if ($module == 'block') {
      $box = db_fetch_object(db_query('SELECT * FROM {boxes} WHERE bid=%d', $delta));
      db_query("INSERT INTO {boxes} (bid, body, info, format) VALUES (%d, '%s', '%s', '%s')", $box->bid, $box->body, $box->info, $box->format);
    }

creating a new block now goes like this:

  $delta = install_create_custom_block($body, $title, $format);
  install_add_block('block', $delta, ...);