LiveFrost dependency and High CPU load

Hi There!

While this library is awesome as a drop-in replacement for UIAlertView, I ran into an issue with LiveFrost causing high CPU load for a displayed alert (https://github.com/radi/LiveFrost/issues/3).  Since the view behind the Alert won't be updating, I disabled live blurring once the view transitions in.  

This required updating to the latest version of LiveFrost, which should be pulled in via the .podspec instead of being imported by hand.  This was added in 1.0.4, which CXAlertView wasn't updated to yet.

It looks like my editor may have squashed some trailing whitespace, so let me know if that's an issue.  Otherwise, thanks for your great work!