Add 3 extra iterations in findIndex

[dschwoerer]

That seems to push the error down to 1e-28.

Resolves #56

[ZedThree]

Is this not just equivalent to reducing the tolerance? Could we just make the default 1e-15 or something?

[dschwoerer]

It seems to be equivalent to reducing it to around 1e-27.
But I am worried that it makes it fail for other cases.
But we could set it to that, and wait for users complaining?

[ZedThree]

That seems like overkill to me, is that what's required to resolve #56? Is the issue with #56 that this tolerance is not a setting exposed to the user?