Need ghistogram

[BruceSherwood]

The graphing package should include a ghistogram option (in lib/glow/graph.js). This could perhaps be similar to matplotlib:

https://matplotlib.org/examples/statistics/histogram_demo_cumulative.html
n, bins, patches = ax.hist(x, n_bins, normed=1, histtype='step',
                       cumulative=True, label='Empirical')

Another possibility is the form of ghistogram in VPython 6:

https://vpython.org/contents/docs/graph.html

There is an example of making a histogram using the existing graphing options:

https://www.glowscript.org/#/user/GlowScriptDemos/folder/Examples/program/HardSphereGas-VPython