* Add x/y/z query arguments to specify MC world coordinates. If world
coordinates are specified, display a POI icon indicating where the
coordinates specified are. Gmaps-style "lat" and "lng" are still
accepted, and will take precedence over x/y/z.
* Expand functionality of the "zoom" query argument. "max" specifies
the maximum zoom, and negative numbers are steps out from max.
Gmaps-style zoom is still supported.
* Change the URL current position area to use x/y/z arguments.
Displayed zoom uses the new zoom logic.
