Issue #1392754 by tss, justAChris, jhodgdon: Comply with new documentation standards for @file for namespaced class files

Issue #2228261 by beejeebus, kim.pepper, alexpott, Wim Leers: Add a local, PhpStorage-based cache backend.

Issue #1675260 by chx, effulgentsia, pwolanin, neclimdul: Implement PHP reading/writing secured against 'leaky' script.