Race chart and political data should update as selections are made

[kshepard]

Overview

Currently the race chart (and political data) in the sidebar is only updating when districts are saved. We have all the data needed to display these changes as selections are being made. This calculation should be tied into the event that updates intermediate population values so these are updated in real time.

Acceptance criteria

• The race chart on the sidebar is updated as selections are made on the map.
• The political data calculation is updated as selection are made on the map.