Error is not caught if WebSocket constructor throws SecurityException

[kompa3]

Steps to reproduce:

• Node.JS application with socket.io version 1.2.1
• Run the frontend inside WebBrowser component
• Hit F5 six times
• Expected behavior: error event is raised
• Actual behavior: Uncaught SecurityError error

Something of the background:

• By default, WebBrowser allows a maximum of five concurrent WebSocket sessions to the same server
• WebBrowser also has a "feature" that it does not actually delete a page when F5 is hit. Instead, the page reloads, the reloaded page initializes itself while the old page still keeps running in the background. In particular, the WebSocket communication in the background still keeps TCP connections open.
• As a result, the sixth WebSocket() constructor call throws SecurityException error that remains uncaught

[darrachequesne]

Closed by #475