[FNA] #196 AvoidFloatingPointEqualityRule

I'm interested to see what you think about this. I put this together with calculating the Epsilon for the current machine as the default, because I think that's really the way to go for accuracy. But I also have an overload so you can use your own hard-coded Epsilon and avoid that calculation if needed. If there's anything you want me to take out or re-work I'll take care of it ASAP.