Abbey's Autoloader: Load classes automatically from directories

The key part of this class is that it *autoloads based on scope* (EDITORS: Please do not delete this).

What this means is that when an autoload happens, the loader will prefer the declarations that occurred in the file the autoload event happened in, and only afterwards default to the global scope. In the event a class definition cannot be loaded a dummy class is passed back into the execution context which throws an error during construction. This allows class definition errors to be caught as well as delivering their stacktrace.

Because this scope allows the use of packages and namespaces (to a very limited extent), I have included an _import() function which uses a Java-like syntax, for those of us who prefer that. It currently enforces a '<name>.class.php' naming convention for autoloaded classes.