Add NixOS module for syslog-ng
New pkg: riemann-c-client version 1.1.1

A C client library for the Riemann monitoring system
New pkg: syslog-ng-incubator

A collection of tools and modules for syslog-ng
syslog-ng-incubator: Update from 0.3.1 to 0.3.3
syslog-ng: Update from 3.5.4.1 to 3.5.6