Integer bins via rounding

Just a first pass at doing integer binning via rounding the edges and passing those into the histogram function. In a situation like [25, 81], this will result in 10 bins with a per-bin width of either 5 or 6. If people aren't fans of this, that's totally fine.

I assume I'm doing plenty wrong, too. Please tear me apart!
I don't really like the idea of throwing a lot of catchall statements to catch weird situations that may or may not exist (other than asserting). I specifically see nulls, here -- maybe that's all we'll get? If you know of situations where we might see undefined and/or NaN here, then I'd be more inclined to agree