Provide UI to help the user find good precincts to add.

[michaelaltmann]

When packing a district, the user needs to find precincts that are biases towards the party being packed. This can difficult then precincts are small or already part of another district. Some options to consider:

• A control where the user could as to highlight all the precincts leaning a particular direction.

• Use a cartogram where precinct size is proportional to population or voting bias.

• Provide a way to show just the outlines of the assigned precincts, so their red/blue coloring coukd still be seen.