clearstatcache change

I think we either need to make clearstatcache() not affect the realpath cache, or we should add an optional argument to it to specify whether or not the realpath cache should be cleared as well. The realpath cache makes a huge difference on includes and having the cache blown away by a script calling clearstatcache() really hurts. In almost all cases the script is doing it to clear the stat cache for some local file it is doing stuff to and the author has no idea that she is blowing away the realpath_cache as well. And if that script is run on every request, the realpath_cache becomes completely useless. -Rasmus