deps: upgrade to npm 2.14.2

THIS UPDATE INCLUDES A SECURITY FIX

Hooray, shiny new npm! See the release notes at https://github.com/npm/npm/releases/tag/v2.14.2 for details!

Aside from that, we fixed up how preferGlobal warnings was working because the unexpected warnings were messing with Windows PowerShell.

As we talked, I didn't include any of the usual cherry-picks -- hooray for not being io.js anymore! Hooray for whatever's happening with the node-gyp stuff!

The extra commit you see is just a patch to our test suite to make it pass when you make test-npm -- a recent patch made it so .npmrc is never included when you pack a repo, and that broke the test suite when not testing directly in source :)

r: @Fishrock123 r: @chrisdickinson