Merge pull request #103 from eyfs/master

Restore extra headers to sendData

Author: barryvdh

src/Message/AbstractRequest.php

@@ -192,7 +192,11 @@ public function getHeaders()
      */
     public function sendData($data)
     {
-        $headers = array('Authorization' => 'Basic ' . base64_encode($this->getApiKey() . ':'));
+        $headers = array_merge(
+            $this->getHeaders(),
+            array('Authorization' => 'Basic ' . base64_encode($this->getApiKey() . ':'))
+        );
+
         $body = $data ? http_build_query($data, '', '&') : null;
         $httpResponse = $this->httpClient->request($this->getHttpMethod(), $this->getEndpoint(), $headers, $body);