Error when sounds are missing

[joevenzon]

I've updated the assert inside Reset in the latest SVN, as there's no reason to check whether or not the soundbuffer exits if the buffer position is just getting reset to zero. I was able to run with -nosound without any problems, but I have all of the sounds. I dunno if you want to try it out and see if there's going to be another assert/segfault somewhere else or just call it good enough now that you have the sounds working.