Address result type mismatch

[dchaley]

The test test_two_image_peaks asserts that out.dtype == _supported_float_type(mask.dtype). Meanwhile the current reconstruct implementation indeed creates the result image as a float, even if it was ints to begin with.

I'm not sure we need to (always?) do this. The core of the algorithm is to adjust to the neighborhood max. The max can't have more precision than any of the starting numbers. And the max can't be capped to more precision than the mask precision. So if ints are masking ints, why not have int results?

However floats masked by ints are floats, and arguably ints masked by floats should be floats. for example 10 mask 0.51 should be 5.1 not 5. (Right?)

The current behavior is to always return floats. This is undesirable for performance as it precludes updating in-place. I wonder if we can simply ship this as new behavior. Downstream usages could be affected if they assume floats and start getting ints. Can we control via "Yet Another Parameter"™️ ?