Need to add software switch to increase MAX_USERS

```
Some users want to increase MAX_USERS on their installations. We need to add a 
software key that allows this to change dynamically while the program is 
running. 

We can do this in fluidWall.cpp

```

Original issue reported on code.google.com by `futureli...@gmail.com` on 20 May 2011 at 4:03
