#52, #53: Add support for raster and vector XYZ tiles. In addition to this support are some extra samples:
 * An OpenLayers 2 example using OpenLayers.Layer.XYZ to consume a Map Definition from the REST API.
 * A leaflet example that consumes a Map Definition from the REST API.
 * An ol3 example that consumes vector tiles from the REST API.

To support the new samples, this submission includes:
 * ol3 beta 5
 * leaflet 0.7.2