Changed URI_BASE to HTTPS

As per
code.flickr.net/2014/04/30/flickr-api-going-ssl-only-on-june-27th-2014/
Flickr's API is moving to SSL-only in the near future. Following this change devs will need to adjust their code to include a Zend\Http\Client and associated adapter. For example:

$HttpClient = new Zend\Http\Client;
$adapter = new Zend\Http\Client\Adapter\Curl;
$adapter->setOptions(array(
"curloptions" => array(
CURLOPT_SSL_VERIFYPEER => false // Verify peer OR verify host + provide
CA file
)
));

$HttpClient->setAdapter($adapter);

$Flickr = new ZendService\Flickr\Flickr($api_key, $HttpClient);