UPDATE: The Vector Tiles are not being served at this time by Openstreetmap. Try later or a different provider (example) Services seem to have resumed
A simple test of extending the L.TileLayer to fetch geoJSON tiles from openstreetmap and render them with d3. This is probably not the most efficient way to do this, as we accept empty image tags (from the standard TileLayer) and use them as containers for the data/requests.