Allow user to filter polling places in their county

[mapsandapps]

Some possibilities to consider:

• [ ] Open now
• [ ] Open today (or tomorrow if it's currently after 9pm, using existing logic)
• [ ] Open on Saturdays
• [ ] Open on Sundays
• [ ] Open Saturdays or Sundays
• [ ] Open after 5pm
• [ ] Open after 6pm
• [ ] Open after 7pm
• [ ] Open after 8pm
• [ ] Open before 9am
• [ ] Open before 8am
• [ ] Open the first week of early voting
• [ ] Open this week
• [ ] Reset filters
• [ ] More?

[mapsandapps]

Should there be a separate tab (alongside "List Closest" and "Map") on the county page for a filtering view?

[mapsandapps]

From Tabitha:

Also merge PR #37 once styled