Fixed Unit Tests

- Skipping tests till run in separate process if fixed
- Making array objects to be compatible with older versions of php

lib/PayPal/Auth/OAuthTokenCredential.php

@@ -143,7 +143,7 @@ class OAuthTokenCredential
     /**
      * Retrieves the token based on the input configuration
      *
-     * @param [] $config
+     * @param array $config
      * @param string $payload
      * @return mixed
      * @throws PPConfigurationException
@@ -183,7 +183,7 @@ class OAuthTokenCredential
     /**
      * Generates a new access token
      *
-     * @param [] $config
+     * @param array $config
      * @return null
      */
     private function generateAccessToken($config, $refreshToken = null)