Support fxcop error codes as per microsoft help

see here
http://msdn.microsoft.com/en-us/library/bb429400(v=vs.80).aspx

"Errors can occur while you are loading items into FxCopCmd for analysis, or during the analysis itself. FxCopCmd does not consider all errors to be fatal. If, despite errors, FxCopCmd has sufficient information to perform a partial analysis, it performs the analysis and reports the errors that occurred. Error messages are sent to the console's error stream, and informational messages about the progress of the analysis are sent to the console's output stream."

So imo only fatal errors should fail a anlysis