Include more detailed info into the Logger.Error(Exception ex, string message, params object[] args) method

At the current moment it only includes Exception.Message into the logged message, what isn't much useful for generic exceptions like NullRefException etc.
It would be better to include stack trace, for instance:
```
Log(TraceEventType.Error, "{0} : {1} - {2}", message, ex.GetType().Name, ex.ToString().Replace("\r\n", " \\r\\n "));
```