protected function addParam($key, $value = null)
	{
		if (is_null($value))
		{
			$this->params[] = $key;
		}
		else
		{
			$this->params[$key] = $value;
		}

	}
protected function addParam($key, $value = null)
	{
		if (is_null($value))
		{
			$this->params[] = $key;
		}
		else
		{
			$this->params[$key] = $value;
		}

	}
protected function addParam ( $ key , $ value = null ) { if ( is_null ( $ value ) ) { $ this -> params [ ] = $ key ; } else { $ this -> params [ $ key ] = $ value ; } }
Adds a wkhtmltopdf parameter

@param string $key
@param string $value
Adds a wkhtmltopdf parameter