Preload is not required by default.

Remove \ArrayAccess interface and remove the three previous autoloader
states. Now we have only one parameter that matters: whether preload is
required or not (thanks to the methods requirePreload() and
isPreloadRequired()). By default, the preload is NOT required.

Thus, we can use the famous from/import calls to preload classes (with
all the benefits: import pattern, such as * or ~, aliases for entry
classes, foreachImport(), etc.) or we can use the autoloader directly. In
all cases, we can use the `use` keyword obviously.
[auto] Merge from Core

    • #ec256a4 — Preload is not required by default. (Ivan Enderlin, 2013-08-23)

---

Merge remote branch 'library-core/master'