FIX - Call to undefined function module_exist error

The module documentation states that the code below should be inserted after the body tag:

<?php if (module_exist('iedestroyer')) { echo iedestroyer_banner(); } ?>

In 5.0.x the function module_exist is now module_exists. The new code should read:

<?php if (module_exists('iedestroyer')) { echo iedestroyer_banner(); } ?>

Tested against 5.0.x-beta2