feature:: Adds support for JSON request

Now RB Framework is compatible with json request. You need to send format=json in url.
For json view, you need to assign content in json variable of view by $view->assign('json', $dataToConvetIntoJSON);
ShowTask function in RB_View is divided in sub-function called _showTask, which will take care of rendering of tmpl file.
For json view tmpl redendering is not required so _showTask function will return '' (empty string).