fix comments for php server example

server/php/example/send_sms.php

@@ -1,6 +1,10 @@
 <?php
 
-// invoke from command line 
+/*
+ * Command line script to simulate sending an outgoing SMS from the server.
+ *
+ * The message will be queued on the server until the next time KalSMS checks for outgoing messages.
+ */
 
 require_once __DIR__."/config.php";