fix(oauth): sort parameters in a standard way as per the specs (#721)

the signature is now calculated a bit differently to match other
implementations.

BREAKING CHANGE: existing OAuth applications may encounter some issues
leading to `invalid_signature` 401 errors from Magento due to the
removal of natural sorting for parameters when generating the signature

lib/Zend/Oauth/Signature/SignatureAbstract.php

@@ -167,7 +167,7 @@ protected function _getBaseSignatureString(array $params, $method = null, $url =
     protected function _toByteValueOrderedQueryString(array $params)
     {
         $return = array();
-        uksort($params, 'strnatcmp');
+        ksort($params);
         foreach ($params as $key => $value) {
             if (is_array($value)) {
                 natsort($value);