nixos: Add option services.cron.cronFiles

This allows you to configure extra files that should be appended to your
crontab. Implemented by writing to /etc/crontab when the cron service starts.
Would be nicer to use a cron that supports /etc/cron.d but that would require
us to patch vixie-cron.
stumpwm: update and refactoring

This commit updates the stumpwm to version 0.9.8. Futhermore, it
refactors the expression quite a lot:

* stumpwm has been moved from lisp modules to window-managers.
* stumpwm has been added to the window managers NixOS knows about, this
  enables the user to add stumpwm as a default window manager in his
  NixOS configuration like with Xmonad or i3.
* the package has been split into stumpwm and stumpwmContrib. This is
  due to the fact that development of stumpwm and its extension modules
  has been split into two repositories. As of today, the release is the
  last one before this split. This split into two packages only reflect
  those upcoming upstream changes already.

It is planned to make the addition of the extension modules voluntarily,
like with Xmonads option "enableContribAndExtras". Furthermore it might
be possible to add an option to compile stumpwm with clisp instead of
sbcl.
stumpwm: removed from lisp-packages.
fix sound in minecraft for pulseaudio users
logstash service improvements

* add logstash-contrib plugins package
* add additional options to the logstash service
Try to fix acpi_call for 3.17
haskell-hinotify: this package is supported on Linux only
git-annex: blind attempt to fix the build on Darwin
spin: update from 6.3.2 to 6.4.1 and add myself to maintainers
haskell-cabal2nix: update to version 1.70
haskell-sloane: update to version 1.9.3

This version supports the latest optparse-applicative.
haskell-git-annex: update to version 5.20140927
haskell-liblastfm: update to version 0.4.1.0
haskell-BNFC: update to version 2.7.0.1
haskell-Ebnf2ps: update to version 1.0.12
dadadodo: adopt and cleanup expression
Fix dadadodo entry in all-packages after cleanup
kde-gtk-config: handle symlinked themes
elasticsearch: fix plugins install
elasticsearch_river_jdbc: 1.2.1.1 -> 1.3.0.4