Userland autoloading is going away

[lexidor]

See: facebook/hhvm@d419828

NF FTW (Native Facts For The Win).

It might be nice to keep this project around for the pseudo-reflection "where's this symbol defined" api. If this is the direction the Meta team wants to pursue, the following steps would have to be taken.

• Release a new version of hhvm-autoload with a minimum hhvm version where autoload_set_paths() stopped working.
• Make initialize() a noop.

The hack Oss world should update their bin/ scripts to stop looking for the autoloader.