Gravity well option

DONT Merge this just yet.  But I think I've got KGW working with Bunnycoin.  I do need to run a few more tests to make sure this will help.  I personally don't think the issue is the need for the gravity well.  I'm wondering if the actual basic retargeting is an issue.  But I wanted to send this pull request so that if you wanted to look at what I modified you had access to it.