Allow multiple binaries (for different platform) to be kept using same folder structure as repo

[umgupta]

There are times when production servers don't have access to npm registry.

In such cases, the only resort is to update node_modules folder on local system and push it to the production server. But now, the problem is one can't keep two binaries (for ex : OSX and Linux).

This can be possible if we keep same dir structure as on this repo. One can download and substitute for the other binary in that case.

Node-Sass follows the same.