Remove unnecessary count()

The value of the lineItems field in the downloadlineitems response will always be a string, so no need to check count(). Instead just verify whether the field exists and is non-empty.

Fixes #10

php/examples/DownloadLineItems.php

@@ -55,7 +55,7 @@ public function run() {
       return;
     }
 
-    if (!isset($result['lineItems']) || count($result['lineItems']) < 1) {
+    if (empty($result['lineItems'])) {
       print '<p>No items found</p>';
       return;
     } else {