* legend:
* allow placing legend below plot (``legend_location=='below'`` or ``legend_location==11``)
* fixes for figure grouping and multi-column plots
* heatmap:
* font and font size fixes
* themes:
* beautification of "white" theme
* allow switching of themes via keyword at the plot call
* allow overloading of default color list in theme file
* other:
* fixed requirements so it will import after install in clean environment
* deal with iterticks warning from ``matplotlib`` versions >= 3.1
* added ``save_data`` keyword to dump a subset of the plotted data only from the original ``pandas.DataFrame``
* file extension bug fix
* filter improvements (allow "not in" list)
* added option to disable alphabetical sorting of data and plot based on the order in which data appears in the original ``pandas.DataFrame``