Invalid ol.BingMapsStyle

According to the doc (http://msdn.microsoft.com/en-us/library/ff701716.aspx), the valid imagerySet values are:
 * Aerial - Aerial imagery.
 * AerialWithLabels - Aerial imagery with a road overlay.
 * Birdseye - Bird’s eye (oblique-angle) imagery
 * BirdseyeWithLabels - Bird’s eye imagery with a road overlay.
 * Road - Roads without additional imagery.

And not OrdnanceSurvey or CollinsBart.

BTW, this list should problably moved to externs/bingmaps.js