Update node/npm to new version

[msecret]

Updates node to version 5.12 and npm to version whatever. Main point
was to update npm to version greater then 3 because of all the features
it adds at that point.

It would be nice to merge this before any package.json updates.

Ref #331

[coveralls]

Coverage remained the same at 70.958% when pulling d83620f on ms-upgrade_npm into ad3e187 on master.

[jeremiak]

I'm concerned about moving to a 5.x branch because the odd numbered branches don't ever enter the NodeJS long term support schedule. Is the goal to get npm anything above 3.0? If so, I can try this with node 6.x and still use npm@3.8?

[jeremiak]

This is great, I'm really impressed with how little had to change to go up two full versions of node! Plus, the way that npm3 handles dependency resolution seems to make a lot more sense and will hopefully lead to even faster install times since dependencies can be shared.