CStringValidator should use mb_strlen

Hi, I'm creating a Hebrew site, and there are many issues with Hebrew characters in Yii.

Once such issue: CStringValidator uses strlen to get string length. It should use mb_strlen, since some Hebrew characters are represented by two characters.

I'm not sure if Yii wants to have the mb_string package as a requirement though.

Maybe another solution would be better?

If you have enough permission you can config php.ini to overload(replace) single byte functions by mbstring functions

You can take a look here for how to configure mb_string overloading: