Just a simple, caching autoloader, for those days when your aren't composer-autoloading your entire classes :)
Just include the smartloader.php file, the only change you should need
is the variable php $classes_root set that to point to the root directory
for your class files, and you are good to go.
This autoloader caches file paths if APC/APCu is enabled, so it doesn't always transverse the filesystem, thereby speeding things up