* Test(ImageOverlay): crossOrigin option to IMG crossorigin attribute
typical values: false (default), true => '', <string> => <string>
now that a string value can be passed to this option.
* Test(TileLayer): crossOrigin option to IMG crossorigin attribute
typical values: false (default), true => '', <string> => <string>
now that a string value can be passed to this option.
* Style(TileLayerSpec): remove commented code
* Style(TileLayerSpec): remove more commented code