Add support for non-square tiles

examples_src/wms-custom-tilegrid-512x256.html

@@ -0,0 +1,13 @@
+---
+template: example.html
+title: WMS custom tile grid 512x256 example
+shortdesc: Example of a WMS layer with 512x256px tiles.
+docs: >
+  WMS can serve arbitrary tile sizes. This example uses a custom tile grid with non-square tiles.
+tags: "wms, tile, non-square"
+---
+<div class="row-fluid">
+  <div class="span12">
+    <div id="map" class="map"></div>
+  </div>
+</div>