Leaflet/Leaflet — pull request #1802 by mourner (2013-06-27 23:43:30+00:00)
Title: TileLayer maxNativeZoom option for scaling tiles on unsupported zoom levels

Implements #1798. Suppose you have a tile layer with maxZoom 18, but you need it up to 20 and OK with scaling of tiles. Then you would do this:

```js
var tiles = L.tileLayer(..., {
maxZoom: 20,
maxNativeZoom: 18
});
```

Tested and seems to work well for both simple tile layers and WMS layers. Thoughts on the API?