Loosen the type of SSH key files

(cherry picked from commit 444a4fb793c67243512a7f17c287e5665a8e2a68)
Mark the value for nixpkgs.system as a default

(cherry picked from commit 9668294eeb57aaeb8220409e154b411263deedd8)
Don't set an initial null root password for Amazon / VirtualBox images

A null password allows logging into local PAM services such as "login"
(agetty) and KDM.  That's not actually a security problem for EC2
machines, since they do not have "local" logins; for VirtualBox
machines, if you local access, you can do anything anyway.  But it's
better to be on the safe side and disable password-based logins for
root.

(cherry picked from commit 4ba7dfde5b79ec835e8739922400b3f5f4f089f2)
Print a reminder to users to set or disable the root password

(cherry picked from commit 20093751ec96b43d87f0850fc3ad541237405564)
Include the NixOS version in the manual

In particular, this will make it clear what version of the manual is
shown at http://nixos.org/nixos/manual/.

(cherry picked from commit 9ef07d859b23840e1a5d7d7125a6982720afa391)
venus.nix: Fix broken startAt option

(cherry picked from commit 658e830674259621ae4dcba25e26c618c27eb4e0)
adobe-reader: Update to 9.5.5

(cherry picked from commit b232825c07b6dbb4b16f37c4a53f170f79374176)
socate: Update to 1.7.2.2, 2.0.0-b6

CVE-2013-3571

(cherry picked from commit 59cad4dc0768d081d291206f8af20c25fe0e047d)
apache-httpd: Update to 2.4.6

(cherry picked from commit 798ce14839437ac3b5d25377bfe696301ad842fc)
linux: Update to 3.4.68

(cherry picked from commit 07ccfe6af87d05c372b10b730f9ee799305d86dc)
linux: Update to 3.10.18

(cherry picked from commit 5098d53db14061c7918ff0b136e1eeb80b40e9e4)
screen: Only depend on PAM on Linux

(cherry picked from commit 25ca1c30e28f076685ce49ab83d3438ba1cdf24f)
Re-introduce mkStrict function in stable branch, as some packages might still be dependent on it (e.g. nixops). Added a warning that the function is obsolete.
Fix EC2 creation script for latest nixops
Fix test deployment in EC2 creation script
Merge remote-tracking branch 'official/release-13.10' into stable