bye bye customFds, hello stdio

Will break "explore" and "help" under Node 0.6, but npm 2 no longer
supports Node 0.6, so it's OK. Partially addresses joyent/node#8492.
rm -rf npm submodule command

Noticed today that 'npm submodule' is broken in npm 2.0.

Went digging, and thought 'Hey, how did this EVER work?'

Dug a bit deeper, and found that this command was actually let go way
back in the summer of 2013, and had been hanging around ever since due
to a glitch in the system.

So, with this patch, we've 'fixed the glitch', removing it from the set
of npm commands.

Fix #6369
remove need{Name,Version} in favor of inlining