Use live.staticflickr.com rather than farm*.staticflickr.com

[samwilson]

In UrlsApi::getImageUrl() the old farm*.staticflickr.com domain name structure is used, and should be replaced with the new live.staticflickr.com. See https://www.flickr.com/services/api/misc.urls.html for details.

(First reported at samwilson/phpflickr-cli#27 )