Darkcoin: new package (v0.9.13.15)

Darkcoin is a privacy-centered crypto-currency.
Update matplotlib to 1.4.2.

matplotlib acquired two new dependencies: mock for testing
and pytz for rendering.
Litecoin: Update to 0.9.3-preview5

Now Litecoin expression lives in a single file, litecoin.nix
debootstrap | 404-fix:  -> 1.0.64, since 1.0.63 disappeared from archive
libpfm & rr: Add packages.
rr: Bump to version 2.0.0 and fetch it from github.
Fix the Vim Plugins Documentation
Fix filename for udev network interface rules

From http://www.freedesktop.org/wiki/Software/systemd/PredictableNetworkInterfaceNames/

You disable the assignment of fixed names, so that the unpredictable
kernel names are used again. For this, simply mask udev's rule file for
the default policy: ln -s /dev/null
/etc/udev/rules.d/80-net-setup-link.rules (since v209: this file was
called 80-net-name-slot.rules in release v197 through v208)
nixos/tests: Fix nfs
Merge pull request #5184 from daogames/tb/fix-systemd-udev-net-rules

Fix filename for udev network interface rules
Revert "Merge pull request #5184 from daogames/tb/fix-systemd-udev-net-rules"

This reverts commit ddeee82b314505a02752d03c91696b491d41986f, reversing
changes made to 75ead8812b6bfb7b5193c6f487562bc9af0dd334.
Merge pull request #5147 from teh/matplotlib

Update matplotlib to 1.4.2.
Merge pull request #5190 from deepfire/debootstrap-version-fix

debootstrap | 404-fix:  -> 1.0.64, since 1.0.63 disappeared from archive
Merge pull request #5008 from nbp/rr

Add rr & libpfm.
Add package pidgin-window-merge
Add chronos, fault tolerant job scheduler for Mesos
mesos: update to 0.21.0
mesos: add docker support
fixes #5198
openvpn: 2.3.4 -> 2.3.6 (CVE-2014-8104)