HTML Decoding doesn't use ENT_QUOTES

In the INP-1278 - Getting issue details... STATUS we've introduced the kUtil::escape method that is used across the system for any type of escaping. However it turned out that we still use plain old htmlspecialchars_decode everywhere without giving the ENT_QUOTES parameter. I bet same with "urldecode" and such.

I propose that we add the kUtil::unescape method that will do the opposite of kUtil::escape.