SignalR/SignalR — pull request #2671 by halter73 (2013-10-31 23:42:54+00:00)
Title: Respond to bad requests with a 400 status code

- Previously bad requests caused PersistentConnection.ProcessRequest to throw
resulting in a 500
- Respond with a 403 status code when the client changes identity
- No longer throwing on bad requests reduces extraneous error logging
- Traces logged by TaskAsynceHelper.Catch are now warnings making it easier to filter out those traces

#2450