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!
FWIW beautiful reduce ;) 

```
return _.reduce(records, (acc, rec) => {
  var value = utils.getIn(rec, path);
  if (_.isFinite(value)) acc.push(value);
  return acc;
})
```