Requires microsoft/azure-storage in v0.15.0 or up

* `ServiceException::getErrorReason()` has been removed since v0.13.0
* `ServicesException` has been moved to `MicrosoftAzure\Storage\Common\Exceptions\ServiceException` since microsoft/azure-storage v0.14.0
* `CreateBlobOptions::setBlobContentType()` has been renamed into setContentType since v0.15.0

composer.json

@@ -3,7 +3,8 @@
     "type": "metapackage",
     "require": {
         "knplabs/gaufrette": "^0.3",
-        "microsoft/windowsazure": "0.*@dev"
+        "microsoft/windowsazure": "0.*@dev",
+        "microsoft/azure-storage": "~0.15"
     },
     "conflict": {
         "microsoft/windowsazure": "<0.4.3"