nixos/statsd-service: fix 'graphitePort' default value

graphitePort must point to the port that carbon-cache listens on, not
the graphite webUI port.

With this change I finally got data from statsd to graphite.
spring: fix runtime dependency on udev
springlobby: 0.186 -> 0.195
Added mirrors for sourceforge.jp.
openra: runtime dependency on systemd
pypy: 2.2.1 -> 2.3.1
nixos-iso: Use a simpler disk label

When formatting a nixos usb using my windows machine I noticed that the
disk labeling using periods was not compatible with my linux kernel /
udev recognition. When labeling a volume NIXOS_14.10 under Windows, it would
show up as NIXOS_14_10 on NixOS. This meant that /dev/root would never come
up at boot time, preventing the livecd from starting.

This patch works around this issue by eliminating any special characters
other than underscores. The previous versioning didn't seem all that
useful, especially when consdering there are many different version of
the year.month named iso.
Allow to keep visudo. Useful for checking sudoers syntax
Enable checking sudoers syntax. Fixes #2850, probably.
Addnig a package to copy nix-prefetch-* to bin/. Hopefully fixes #1130
kernel: Add 3.15
Merge branch 'master' into nitrogen
Merge branch 'master' into typespeed
Merge branch 'nitrogen' into typespeed
Oops, got nitrogen and typespeed branches mixed up.
Removed unneeded builder.sh.
hdevtools compiles
Add MFlow and dependencies
Fixed problem with worddir and ruledir path.
Oops, forgot to add patch.