TbModal: Added support for iframe if attribute 'remote' is an absolute u...

Usage:

 ``` php 
$this->widget('bootstrap.widgets.TbModal', array(
    'buttonOptions' => array('label'=>'Yii framework'),
    'remote'=>'http://www.yiiframework.com/',
    'iframeWidth'=>600,  // in px, default is 800
    'iframeHeight'=>300,  //in px, default is 600
));

//in CRUD operations/views, when want to refresh after creating a related model (maybe to update dropdownlists)

$this->widget('bootstrap.widgets.TbModal', array(
    'buttonOptions' => array('label'=>'Add item'),
    'remote'=>Yii::app()->createAbsoluteUrl('member/create),
    'onHide'=>'document.location.reload()',
));
 ```