This is a drop-in replacement that handles nodejs recursive dependencies by
propagating already visited nodejs packages and creating shims for recursive
ones. This implementation handles both, new and old npm2nix output format.
This is because of an error while using `nix` under Archlinux:
```
building path(s) `/nix/store/rwkcbhv9jfhzhandfslg62knl2xw0r7m-node-sources'
building /nix/store/rwkcbhv9jfhzhandfslg62knl2xw0r7m-node-sources
suspicious ownership or permission on `/nix/store/rwkcbhv9jfhzhandfslg62knl2xw0r7m-node-sources'; rejecting this build output
cannot build derivation `/nix/store/01qsszx9y2kyx1x72zr5magy2la98720-uglify-js-2.4.15.drv': 1 dependencies couldn't be built
```
The permissions on all file are like the following:
```
drwxrwxr-x 1 root root 358 Jun 9 17:04 .
drwxr-xr-x 1 root root 421110 Jul 21 15:49 ..
-rw-rw-r-- 1 root root 22 Jun 9 17:04 .gitattributes
```
After the fix, permissions are OK, and no suspicious error any more.
Error is encountered for any node package built. I'm not sure why it
fails on Arch but work on nixos, but I believe the flag is safe to add
anyway.
buildNodePackage is a function to build npm packages.
npm2nix (https://bitbucket.org/shlevy/npm2nix) can be used to generate subexpressions to go in node-packages.nix
