Update MapBox basemaps

[pomadchin]

Demo URI: https://pointcloud.geotrellis.io/

At this point Azavea basemap is not available:
i.e. the following query https://b.tiles.mapbox.com/v3/azavea.map-zbompf85/12/833/1610.png returns the following message:

{
  "message": "Classic styles are no longer supported; see https://blog.mapbox.com/deprecating-studio-classic-styles-d8892ac38cb4 for more information"
}

WroldLight base map is not accesible anymore:

i.e. http://c.tiles.mapbox.com/v3/mapbox.world-light/12/833/1610.png returns the following message:

{
  "message": "Unauthorized"
}