Capture and report errors in background processes (loader, updater) as we do in foreground (render).
Add custom TraceListener which formats Exceptions just like TraceError. Use Trace.WriteLine(error) to trigger.
git-svn-id: http://svn.uktrainsim.com/svn/openrails/trunk@308 a9f3cfff-6c41-7446-b0ca-052bd761e6eb