Suggested GUI tweak

```
I find it difficult to see the FPS counter at times, so I wrote a method 
similar to DrawText in SimContext.cpp that draws a contrasting rectangle behind 
the text, eliminating the possibility of a the FPS text being invisible against 
a matching background. I've attached the code.


```

Original issue reported on code.google.com by `Luc4sDre...@gmail.com` on 10 Nov 2013 at 10:17
