Fix: XSS issue in Flash

- Reading a flashvar without escaping it appears to be a sure fire way
  of introducing an XSS vunriblity into your code. Crazy that it is
  effectively insecure out of the box, but there we go.

- Thanks to Hip (Insight-labs.org) and Tobias Bäthge for discovering
  this and letting me know.

- More information can be found here:
  https://github.com/jonrohan/ZeroClipboard/issues/14