Added default language pack (en-gb)

catalog/api/reward.php

@@ -0,0 +1,9 @@
+<?php
+// Text
+$_['text_success']     = 'Success: Your reward points discount has been applied!';
+
+// Error
+$_['error_permission'] = 'Warning: You do not have permission to access the API!';
+$_['error_reward']     = 'Warning: Please enter the amount of reward points to use!';
+$_['error_points']     = 'Warning: You don\'t have %s reward points!';
+$_['error_maximum']    = 'Warning: The maximum number of points that can be applied is %s!';