Bias autocomplete to chicago

[kalilsn]

Right now the autocomplete dropdown is biased based on your gps location, but that's unreliable and unnecessary. We should replace that code with hardcoded bounds for the city of chicago and consider setting strictBounds.

@jeancochrane suggests taking the coordinates for the Loop and adding a radius of ~20 miles, which is roughly the distance from the Loop to the furthest community that includes routes on our map (Hegewisch).