FieldLogViewer UI option: Show thread ID column, web request ID, or none; Same-request highlighting
Use of StringBuilder; adding FieldLog version in LogStart scope items
ASP.NET: Optional DNS reverse lookup of the client host address
Web request handling refactored

* Web request identification data moved from [ThreadStatic] to HttpContext.Items
* WebRequestEnd has the response status code and client disconnection in its scope name, also showing in the log items list