0.2.0

• Added APCu adapter
• Version requirements bumped to ones that reflect fully available functionality. More specifically:
  • APC 3.1.1 is now the required minimum (previously, 3.0.13), because it's the minimum for APCIterator.
  • APCu 5.0.0 is required, because of APCUIterator, though 4.0.0 would be sufficient for the rest.
  • PHP 5.3.9 is the minimum required PHP version, because it is the firt one in which a critical bug affecting this package is fixed. See #43200 for details.
• Doc and CS fixes.