Revert c109400 (ExtensionClass getstate) on the stable branch, until http://dev.plone.org/plone/ticket/10318 has been fixed

Hoping that silence (or apathy?) is consent here. :) Adding an event to indicate when streaming is starting in case of chunked/streamed responses using response.write()

Fix a bug where resources in sub-directories of resource-directories would not be traversable via restrictedTraverse() due to missing security wrappings.

fix regression in traversing to 'macros' on template-based browser views, which crept in somewhere on the way to 2.12