some more blacklisted attributes

[LDAV]

noshade is blacklisted for hr tags
align is blacklisted in p tags

in alternative, you can add an apply_filters:

private function get_blacklisted_attributes() {
  $args = array('style');
  return apply_filters('amp_blacklisted_attributes', $args);
}

[mjangda]

Closing as we've moved to a whitelist-based approach #600