Update libs/NiftyGrid/GridPaginator.php (~based on: 

hi,

this is feature for: GridPaginator() to use better setting of template by $templatePath.
it's inspired by practical usage and existing pullrequest ~ https://github.com/Niftyx/NiftyGrid/pull/32 .

difference between "vinam" and "j3nda" is:
- public function __construct($templatePath = null)
- protected function setTemplate($templatePath)