Version 0.4.3

Additions

• Adds the nd_freeze utility for (Neuro)Debian base images. This allows users to pin the apt sources to a particular date and time and is very useful in creating reproducible builds. Otherwise, calls to apt-get update make builds non-deterministic (#240).

Fixes

• Wraps pip and conda packages in single quotes. This prevents the execution of shell commands like > in numpy>=1.10 (#239).