minor cleanup
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
tweak locker logging for readability
log what is and isn't in flight
wait to put Git URLs in flight until normalized
only make cache creation requests in flight
style tweaks
log errors on multi-{install,build}

And in the case of installs, log which versions have already been
installed to that path.
update changelog for npm@2.1.3
2.1.3