Include Baltimore CA cert by default

[stefangordon]

We should include the cert for Azure as many users will integrate with Azure IOT services. This can be pulled from https://www.microsoft.com

[ladyada]

heya, i forked, and added the baltimore here https://github.com/adafruit/WiFi101-FirmwareUpdater
i tested it and could ssl to anprice-iothub.azure-devices.net

[stefangordon]

Great!