Upgrade npm to 1.1.6

* Fix #472 Adds support for os/cpu fields in package.json (Adam Blackburn)
* Don't use existing pkg if explicit
* Install missing deps, even if they are in bundleDependencies
* bundle node-gyp
* Automatically node-gyp build stuff with a bindings.gyp
* Fix #2230 Unpack in place. No folder renaming malarky
* Never create un-listable directories
* Fix cases where an optionalDependency fails to build
* Always ignore .wafpickle-7 files
* fix shrinkwrap test
* Fix: bundleDependencies being re-installed unnecessarily