support for postgresql

[lluis]

Hello, I've added support for postgresql, you can switch mysql/postgresql changing an option in config.php

//$DB_DATABASE = "postgresql";
$DB_DATABASE = "mysql";

also added a sql script compatible with postgres, but maybe there's a way to write a sql script compatible with both sql servers...

regards, Lluís

[lluis]

images are not yet stored/retrieved correctly from postgres