Adds ability to specify additional arguments to PHP process running the cron job

An example use case for this is the need to pass INI settings to PHP when it runs the cron so they don't affect the application when running normally through Apache:

    /var/www/html/cron.sh cron.php '-d memory_limit=5120M'

With my changes to cron.sh the above translates into the following:

    /usr/bin/php -d memory_limit=5120M /var/www/html/cron.php