locate service: allow customisation

Fixes #2961
virtualbox: Fix permissions for /dev/vboxdrvu

See https://bugs.archlinux.org/task/38314 and https://www.virtualbox.org/browser/vbox/trunk/src/VBox/Installer/linux/installer-common.sh?rev=47894#L28
fix openjdk url for Darwin
Add ZNC module. Has zncConfOptions or specify full conf file.
Add `NIX_MYENV_NAME` environment variable in `myEnvFun`
Adds easy-format
use wrapper to set LUA_PATH variable
added lua-filesystem-1.6.2
include share directory
Add inferno, a distributed cross-platform hosted OS
vcprompt: new package

This adds the vcprompt utility, a little C program that prints a short string
with barebones information about the current working directory for various
version control systems.
mutt: update to 1.5.23

This commit rewrites the expression somewhat:

- it tries to simplify the expression.
- it changes from fetchurl to fetchhg.
- a patch to configure.ac is added in order to enable configuring the
  source on NixOS.
mutt: added mailpath.patch.
zfs.git: Fix vdev_id error when plugging in a disk (#3161)
Get all lib functions from lib, not pkgs.lib, in modules
python: 2.7.7 -> 2.7.8
python: link gcc_s

Signed-off-by: Domen Kožar <domen@dev.si>
Merge pull request #3160 from cstrahan/vcprompt

vcprompt: new package
Merge pull request #3164 from 1126/master

mutt: update to 1.5.23
Merge pull request #3151 from flosse/lua5-filesystem

added lua-filesystem-1.6.2