Adds a Target attribute to all links in passed content.

This function by default only applies to “ tags, however this can be
modified by the 3rd param.

*NOTE:* Any current target attributed will be stripped and replaced.

function links_add_target( $content, $target = '_blank', $tags = array( 'a' ) ) {
	global $_links_add_target;
	$_links_add_target = $target;
	$tags              = implode( '|', (array) $tags );
	return preg_replace_callback( "!]*)?)>!i", '_links_add_target', $content );
}