HistogramBins

Bins for a histogram. These can be implicitly constructed from:

 x : HistogramBins = 10  // 10 dynamically determined histogram bins
 x : HistogramBins = Array(1.0,2.0,3.2) // five buckets wit the given splits
 x : HistogramBins = (0,100,10) // ten bins evenly dividing 0 to 100.