Add new cacheSize option to ol.source

Option added to:
 - olx.source.BingMapsOptions
 - olx.source.MapQuestOptions
 - olx.source.OSMOptions
 - olx.source.StamenOptions
 - olx.source.TileArcGISRestOptions
 - olx.source.TileImageOptions
 - olx.source.TileJSONOptions
 - olx.source.TileWMSOptions
 - olx.source.VectorTileOptions
 - olx.source.XYZOptions
 - olx.source.WMTSOptions
 - olx.source.ZoomifyOptions

src/ol/source/stamensource.js

@@ -103,6 +103,7 @@ ol.source.Stamen = function(options) {
 
   goog.base(this, {
     attributions: ol.source.Stamen.ATTRIBUTIONS,
+    cacheSize: options.cacheSize,
     crossOrigin: 'anonymous',
     maxZoom: providerConfig.maxZoom,
     // FIXME uncomment the following when tilegrid supports minZoom