Initial change for histogram issue.
changed NB filename so that it doesn't get overwritten.
Removed histogramx and histogramy objects. updated NB for clarity.
Added old method of making histograms for comparison in NB, works.
Removed html files bc etienne is the man.
Added license.txt and setup.cfg files for PyPI uploads.
Histogram works now.
Merge branch 'iss-histogram' into 1.0

graph_references changes, we don't allow histogramx and histogramy
anymore.

new histogram object.