Make sure numerically-close float function parameters are treated as identical

[phargogh]

We sometimes have floating-point parameters such as bounding boxes or coordinate pairs that are represented by floating-point objects. If these are interpreted as floats by taskgraph, it's possible that we might be recomputing a task based on parameters that might differ, but only differ by a numerically insignificant quantity.

If this is the case, we should only recompute if the float is significantly different from the old float, but offer a flag to do as-is comparison.

In the case of a parameter like a bounding box, it would also be nice for the comparison to happen on a per-element basis.