Use permanent Bing Maps API key

This key is registered for "Not-for-Profit" use by OpenLayers as a project of OSGeo - a 501(c)(4) organization.

See the complete [Terms of Use](http://www.microsoft.com/maps/product/terms.html) under the Eduction or Non-Profit Organization Use section.

examples/bing-maps.js

@@ -13,7 +13,7 @@ for (var i = 0; i < styles.length; ++i) {
     visible: false,
     preload: Infinity,
     source: new ol.source.BingMaps({
-      key: 'Ar33pRUvQOdESG8m_T15MUmNz__E1twPo42bFx9jvdDePhX0PNgAcEm44OVTS7tt',
+      key: 'Ak-dzM4wZjSqTlzveKz5u0d4IQ4bRzVI309GxmkgSVr1ewS6iPSrOvOKhA-CJlm3',
       style: styles[i]
     })
   }));