3arcade PHP game script updated to version 2.1 to work with PHP 5.6

I have an installation of the 3arcade script that’s still in the wild, and decided it was time to update it to work with PHP 5.6 (at least).

These changes fix:
– a row 0 error in play.php linked to deprecated functions
– deprecation of the ereg_replace function through use of intval
– deprecation of the mysql_connect function (and future deprecation of mysql* functions) through use of PDO
– consistency of database connection and query errors with a variable in the config file

Changes live at https://github.com/withdave/3arcade