Change the default value of programs.ssh.forwardX11 to false.

Forwarding X11 to untrusted servers is extremely insecure; see for example
http://www.hackinglinuxexposed.com/articles/20040705.html
Remove unnecessary toPath that breaks with recent nixUnstable
dnsmasq: Add extraConfig option
Merge master.
Fixed the documentation for programs.ssh.forwardX11 to account for the X11 SECURITY extension.
Merge pull request #40 from falsifian/master

Change the default value of programs.ssh.forwardX11 to false.
Merge commit 'refs/top-bases/experimental/postfix' into experimental/postfix

# By James Cook (2) and others
# Via James Cook (2) and Peter Simons (1)
* commit 'refs/top-bases/experimental/postfix':
  Fixed the documentation for programs.ssh.forwardX11 to account for the X11 SECURITY extension.
  dnsmasq: Add extraConfig option
  Remove unnecessary toPath that breaks with recent nixUnstable
  Change the default value of programs.ssh.forwardX11 to false.