InvalidArgumentException for-loop over empty arrays

[brunobraga]

While testing the library, I noticed this error when loading the h2o-php/example/i18n/index.php page:

Fatal error: Uncaught exception 'InvalidArgumentException' with message 'The for tag cannot iterate over the value: ' in h2o-php/h2o/tags.php:137
Stack trace:
#0 h2o-php/h2o/nodes.php(27): For_Tag->render(Object(H2o_Context), Object(StreamWriter))
#1 h2o-php/h2o/tags.php(172): NodeList->render(Object(H2o_Context), Object(StreamWriter))
#2 h2o-php/h2o/nodes.php(27): For_Tag->render(Object(H2o_Context), Object(StreamWriter))
#3 h2o-php/h2o.php(136): NodeList->render(Object(H2o_Context), Object(StreamWriter))
#4 h2o-php/example/i18n/index.php(44): H2o->render(Array)
#5 {main}
  thrown in h2o-php/h2o/tags.php on line 137

The issue happens because the index.php contains an empty array() for one of the user.tasks (3rd). The error does not happen if the array is not empty.

From version:
commit 93eee9c