Do we need node-fs-extra?

[arielshaqed]

In the #130 review @michaeladda and @rylandg discussed some rough edges in using node-fs-extra to copy files. The ncp function there is suspect: apart from verifying existence to decide whether to delete before copying instead of opening with O_WRONLY|O_TRUNC (a classic TOCTTOU error), it also copies file permissions across (https://github.com/jprichardson/node-fs-extra/blob/a37d7bbe1c62e5fc2c20212678f4bbd41fc9e202/lib/copy/ncp.js#L99). This is plain wrong: the source file might not even share user and groups, so copying mode won't work. And umask should anyway apply to the mode, so it most likely won't even do the wrong thing it wants to do.
Do we need to use this? It exhibits unPosixan behaviour, and is very surprising to the end-user.

[rylandg]

I will explore this but it's very low priority for me.

That being said. If we do choose to omit using it we should probably enforce that org wise?