Fixing an error on IE when window.Event is defined by user.
Fixing an error on IE when window.Event is defined by user.

hanicker/web-socket-js,nitzo/web-socket-js,gimite/web-socket-js,zhangxingits/web-socket-js,gimite/web-socket-js,hanicker/web-socket-js,hehuabing/web-socket-js,zhangxingits/web-socket-js,gimite/web-socket-js,keiosweb/web-socket-js,hehuabing/web-socket-js,hanicker/web-socket-js,nitzo/web-socket-js,keiosweb/web-socket-js,hehuabing/web-socket-js,nitzo/web-socket-js,keiosweb/web-socket-js,zhangxingits/web-socket-js