Memory-related goodies

A few things are included in this distribution.

1. a file named mem.php is in the root directory (the same directory as the index.php file) of this distribution. When you navigate to this file (http://yourdomain.com/mem.php) you will see a number in the upper left corner of your browser. This number corresponds to the approximate amount (+- 20%) of memory in MB being used by your site.
2. in the settings.php file, we have added a setting that increases the amount of memory available to PHP -- while this will only work with hosting companies that allow you to override the default PHP settings by using ini_set, it will help you avoid any issues related to memory problems.