Update source/reference_manuals/active/deployment/stack.rst
Update source/troubleshooting/buildout.rst

Distribute / setuptools tries to mess with system Python and Permission denided
Update source/troubleshooting/buildout.rst

UnboundLocalError: local variable 'clients' referenced before assignment
Update source/hosting/varnish.rst

Updated for Varnish 3.x
Update source/security/permissions.rst

Using reserved python names as variable names is bad style.
Update source/serving/http_request_and_response.rst

Typo (minor)
Add a section on using orderObjects()