Fix ore update radius

Now I wasn't entirely sure if the problem is rectified, but I got it good up to this:

http://www.youtube.com/watch?v=jyrCOoSgDJY (I first show before and after to see the difference).  The ores still regenerate in the chunk, but instead, they don't regenerate within x blocks, which I think still serves the purpose of the update radius.

Excuse me for the long PR message...