Tax increase-decrease visualization

[rickecon]

@DoraSzasz and @hayleefay have created a dynamic visualization using Bokeh for the first table of Tax-Calculator output that @hayleefay could incorporate as part of the standard output of Tax-Calculator. A screenshot of the visualization is below, a working version of it is on this Heroku gallery page, and the code is in this repository in the /increase_decrease/ folder.

The data in the lower chart are taken from the "Tax units with tax increase" and "Tax units with tax decrease" columns. The data in the upper chart are taken from the "Average tax change" column. The slider bar at the bottom of the page goes through the 10 years of the budget window. There are a lot of other options that could be included in this visualization. Let @hayleefay know if you want her to update it. @MattHJensen @martinholmer

[hdoupe]

These are cool visualizations. We are re-thinking how we want to present the results for TaxBrain. Once we have a better strategy for this, we will look into adding these plots or some like it. In the meantime, feel free to see if the Tax-Calculator project is interested in adding this as a plot capability.

cc @rickecon @hayleefay @DoraSzasz