Extract libraries to an separate extension.

assets/leaflet-loading/README.md

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+Leaflet.loading
+===============
+
+Leaflet.loading is a simple loading control for [Leaflet][]. An unobtrusive
+loading indicator is added below the zoom control if one exists. The indicator
+is visible when tiles are loading or when other data is loading, as indicated by
+firing custom events on a map. The indicator can be an image, or a [spin.js][] spinner (image-less).
+
+
+## Usage
+
+Leaflet.loading is only tested on Leaflet version 0.6 or greater. It will almost
+certainly not work with older versions of Leaflet.
+
+Include `Control.Loading.js` and `Control.Loading.css`, then create a map with `loadingControl: true` 
+in its options. 
+
+By default, Leaflet.loading expects an image. `Control.Loading.css` contains a 
+start in this direction. The simplest case would be adding a 16 x 16 loading gif
+in `.leaflet-control-loading`.
+
+You can also set `spinjs: true` in the options, and load [spin.js][] 
+to use that instead of an image. A spin.js options object can be passed as the spin key 
+when initializing the control.
+
+Whichever method you use, make sure you only use one.
+
+Once the above is complete you will have a loading indicator that only appears
+when tiles are loading. 
+
+If you want to show the loading indicator while other AJAX requests or something
+else is occurring, simply fire the `dataloading` event on your map when you 
+begin loading and `dataload` when you are finished loading. The control tracks 
+the number of concurrent loaders, so it is your responsibility to ensure that 
+the `dataloading` and `dataload` are called symmetrically.
+
+### Options
+
+ - **position**: (string) Where you want the control to show up on the map (standard
+   Leaflet control option). Optional, defaults to `topleft`
+ - **separate**: (boolean) Whether the control should be separate from the zoom
+   control or not, defaults to false.
+ - **zoomControl**: (L.Control.Zoom) The zoom control that the control should be
+   added to. This is only necessary when adding a loading control to a zoom 
+   control that you added manually and do not want a separate loading control.
+ - **spinjs**: (boolean) Enable the use of [spin.js][]. Optional, defaults to `false`
+ - **spin**: (object) A [spin.js][] options object. Optional, defaults to 
+
+    ```
+    { 
+        lines: 7,
+        length: 3,
+        width: 3,
+        radius: 5,
+        rotate: 13,
+        top: "83%" 
+    }
+    ```
+
+
+## Demos
+
+See Leaflet.loading in action (zoom or pan to make tiles load):
+
+ - Using the [simplest setup][simple], with the loading indicator attached to
+   the zoom control.
+ - With the loading indicator [separate][] from the zoom control.
+ - With the loading indicator and zoom control on the [top right][topright] of
+   the map.
+ - The [simplest example using spin.js](http://ebrelsford.github.io/Leaflet.loading/spinjs.html) instead of an image
+
+
+## License
+
+Leaflet.loading is free software, and may be redistributed under the MIT
+License.
+
+
+ [Leaflet]: https://github.com/Leaflet/Leaflet
+ [spin.js]: https://github.com/fgnass/spin.js/
+ [simple]: http://ebrelsford.github.io/Leaflet.loading/simple.html
+ [separate]: http://ebrelsford.github.io/Leaflet.loading/separate.html
+ [topright]: http://ebrelsford.github.io/Leaflet.loading/topright.html