* Remove ErrorReporter.Error, replace with AutomationException with Error Code.
* Move ErrorCodes to AutomationException.
* Don't return exit codes. Solely rely on exceptions to propagate exit codes.
* Remove MainProc delegate
* Remove setting of Environment.ExitCode as it is ignored when main returns an int.
* ShutdownLogging is nothrow, as all exceptions would be ignored anyway.
* Wrap all shutdown steps so further ones get a chance to run.
* Move HostPlatform.Initialize into the global try/catch block
#codereview:ben.marsh
[CL 2605826 by Wes Hunt in Main branch]
