npm prepare script

[paulyoung]

I think the root cause of an issue I'm seeing is that the prepare script of some of my package dependencies aren't run.

[adnelson]

This file would (I believe) be the one to either modify or duplicate to support additional hook behaviors: https://github.com/adnelson/nixfromnpm/blob/master/nix-libs/nodeLib/tools/execute-install-scripts