NODE_PATH support

[cguinnup]

Greetings,
Currently noderify ignores modules in NODE_PATH ( https://nodejs.org/api/modules.html#modules_loading_from_the_global_folders ), neither bundling them in nor reporting that it can't find them. Would you accept a PR to add NODE_PATH support?

[dominictarr]

oh, that is so legacy. that is like, from node@0.2 days!

but anyway, this module uses https://github.com/substack/module-deps to find the modules so you should make the PR to that instead.