Made monster spawning code in cWorld.cpp a bit more compact and readable
srand() is only supposed to be called once in the whole program, and it's already called in the constructor of cWorld so it doesn't have to be in cWorld::Tick()
git-svn-id: http://mc-server.googlecode.com/svn/trunk@14 0a769ca7-a7f5-676a-18bf-c427514a06d6