use yii datetime parser (+default date +exception) 


* use [yii datetime parser](http://www.yiiframework.com/doc/api/1.1/CDateTimeParser#parse-
detail) instead of [php
DateTime::createFromFormat](http://php.net/manual/en/datetime.createfromformat.php)
 * default date format changed to `Yii::app()-
>locale->getDateFormat('short')`
 * CException throw if failled parsing dates (in previous version
validation succeded!)