public function attachFile($path, $alias=null, $cid=null) {
		$this->smtp->attach($path,$alias,$cid);
	}
public function attachFile($path, $alias=null, $cid=null) {
		$this->smtp->attach($path,$alias,$cid);
	}
add a file attachment
@param $path
@param null $alias
@param null $cid