incorrect npm url in install templates

[Example.](https://github.com/jonschlinkert/arrayify-compact#install)

[Cases.](http://git.io/s_Mhwg)
`npmjs.org` should be replaced with `https://www.npmjs.com/`.
Also - `https://npmjs.org/doc/json.html` should be replaced with `https://docs.npmjs.com/files/package.json`.

Won't send PR cause of #3.
