Add the "http-cache": True parameter in the backend json definition to activate.

It seems the only tool supporting http://tools.ietf.org/html/rfc5861

Conflicts:
	component/imagemagick/buildout.cfg
	software/erp5/software.cfg
	stack/erp5.cfg

(cherry picked from commit 198aebba)

Because "gets is a security hole - use fgets instead" and this function is not
available anymore in recent environments.

Also depend on patch change, as it shall lead to recompilation.
(cherry picked from commit 70859841)

stick to Zope 2.12.22 because Zope 2.12.23's ObjectManager.__getitem__ is much slower for a module having lots of sub objects.