subrepo: Add patch to turn off mercurial subrepo handling.

requirements: added ipdb (0.10.1) support.

nix: Move shell hook from default.nix -> shell.nix and set custom shell prompt.

release: merge back stable branch into default

Added tag v4.4.2 for changeset 24ffe44a27fc

release: Finish preparation for 4.4.2

release: updated pip2nix output for 4.4.2

release: Start preparation for 4.4.2

nix: Use --set instead of --prefix for setting the PATH / PYTHONPATH Using --set will not append the system PATH / PYTHONPATH to the environment variable during wraping of executables. This will "lock-out" programs and python modules from the system and only allow the ones which are set during wrapping. This means e.g. of git we make only our custom git available and if thats missing we get an error instead of silently using the system git (if installed)

nix: Use --set instead of --prefix for setting the PATH / PYTHONPATH Using --set will not append the system PATH / PYTHONPATH to the environment variable during wraping of executables. This will "lock-out" programs and python modules from the system and only allow the ones which are set during wrapping. This means e.g. of git we make only our custom git available and if thats missing we get an error instead of silently using the system git (if installed)