location should not be a special name, but should be a type (distance search fails with nested location)

[ultrasaurus]

the app is currently hard-coded to geo-code & search for special field "location" at the root. Quick workaround for this to to change the data.yaml to have location at root (not nested under 'school')

[yozlet]

There's a related problem: at the moment, the code automatically coerces fields with location in their name to float, even if the type is set otherwise. Instead - until the overall issue here is fixed - we should remove those coercions and add a fail at index time if we see a location field that isn't set to float in the data.yaml. (And once location stops being special, we can remove that check)