Infinite loop

Hi,

I found a small set of points in real world data that causes miniball to enter into an infinite loop.

I was going to patch the problem before submitting a pull request, but I've been busy and I thought you might have a better idea of what should be done.

From what I can tell, the stopping condition isn't a good enough check, when the change gets close to epsilon, 'scale' can become zero, this bit:
      Float scale = find_stop_fraction(stopper);
Seb.C:222

I made a small test program called test_1.C, its in this branch with a very basic Makefile.

cheers,
Paul