Start work on better data loading

Load markers synchronously and then load collision data as an
XMLHttpRequest.
Add new collisions to the Oakland database
Add new locations
Split data multiple JSON files
Remove all collisions before adding more
Solve the case of the disappearing markers

Simplify the way that JSON is generated for data and always output all
JSON files at once to ensure markers are in order. Also, never sort the
main marker array, as that will throw off future Collision marker
indexes in data that hasn't loaded yet.