[ut3] Shutdown Error

[Ryan C. Gordon]

> appError called:
> 
> Detected negative delta time - on AMD systems please install 

Is it possible that your system clock adjusted? Like an ntp daemon moved 
it back a couple of seconds?

On Windows, this error is due to the rdtsc not being reliable on 
multicore systems (and a patch from AMD to fix it), but we use 
gettimeofday() on Linux to decide how much time has elapsed between ticks.

--ryan.