Implement npm-fetch into npm

[robertkowalski]

Development of npm-fetch will take some more time.

However I wanted to ask for your opinion to start using the finished parts of npm-fetch in npm - to lower the risk of producing waste and having the disadvantages of two codebases in parallel.

What do you think about it?

[ForbesLindesay]

I agree, lets make the shift to streams as the return value, rather than being callback based, then I think we can replace large amounts of the cache module with npm-fetch.

[ForbesLindesay]

I think in theory we're now ready to start replacing vast swathes of npm-cache with this module. It certainly should be possible to get started and then see what we're missing.

[robertkowalski]

Do you want to have the honor or should I start (would start with local files)?

[ForbesLindesay]

start