vagrant: add expression
ntopng: new package

ntopng is a high-speed web-based traffic analysis and flow collection
tool. ntopng => ntop next generation.

http://www.ntop.org/products/ntop/
nixos: add ntopng service

ntopng is a high-speed web-based traffic analysis and flow collection
tool. Enable it by adding this to configuration.nix:

  services.ntopng.enable = true;

Open a browser at http://localhost:3000 and login with the default
username/password: admin/admin.
Fix a lots of evaluation errors on Hydra.
renpy: update to 6.16.3
amsn: update from 0.98.4 to 0.98.9
libgtop: update from 2.28.4 to 2.28.5
gnome.gvfs: update from 1.14.1 to 1.14.2
diffstat: update from 1.45 to 1.58
Add shellinabox
k3d: fix changed URL/patch
Fix more evaluation errors on Hydra.
dragonegg: fix build via update to 3.3
Fix a minor bug in fsg
apr: Update to 1.5.0
linux: Update to 3.4.73
Add initial configuration for Google Compute Engine
Remove a hardcoded SSH public key from the Google Compute image.
fail2ban: Fix preStart action

Creating /run/fail2ban didn't work since it didn't have write
permission to /run.  Now it does.

Reported by Thomas Bereknyei.
dmidecode: set meta.platforms to linux