This option must be used to set the trusted certificates which gonna be
used by slapos.libnetworkcache to filter the content retrived from shadir.
It accepts multiple lines.

Well, according to the developing done in:
  - https://git.erp5.org/gitweb/slapos.libnetworkcache.git/shortlog/refs/heads/signature?js=1

It is required to build M2Crypto, otherwise it is not possible to use
the signature feature provided by slapos.libnetworkcache.

Source: git://gitorious.org/slapos/slapos-software-xwiki.git

This avoids generation of bin/buildout script, as the original one is just
good enough.

add numpy egg, as websockify (novnc core) requires it for new HyBi-10 WebSocket protocol (coming with Chrome 14 and Firefox 7)

Need to allow from www.owlfish.com, as WSGIUtils is available there.

this option was making git unusable behind a proxy

"gzip" is undefined. Not working stuff should not be in master
branch, so revert this work.
This reverts commit dcc93a3b.