User is unable to install dotfiles globally via npm

Hi @eduardolundgren,

I haven't had a chance to install xcode yet (I just got a new macbook pro retina ^_^ && waiting for a cracked version of version 6). I'm suspecting that's the cause of this bug. Do you know anyone else without xcode installed that can confirm?

EDIT: I just installed xcode & command line tools, but the same failure occurs. I ended up just cloning the repo and calling `bin/dotfiles setup`.

```
marc$ sudo npm install -g dotfiles
/usr/local/bin/dotfiles -> /usr/local/lib/node_modules/dotfiles/bin/dotfiles
npm ERR! peerinvalid The package http-server does not satisfy its siblings' peerDependencies requirements!
npm ERR! peerinvalid Peer dotfiles@0.6.1 wants http-server@~0.5.5

npm ERR! System Darwin 13.3.0
npm ERR! command "node" "/usr/local/bin/npm" "install" "-g" "dotfiles"
npm ERR! cwd /Users/marc/dotfiles
npm ERR! node -v v0.10.31
npm ERR! npm -v 2.0.0-beta.0
npm ERR! code EPEERINVALID
npm ERR!
npm ERR! Additional logging details can be found in:
npm ERR! /Users/marc/dotfiles/npm-debug.log
npm ERR! not ok code 0
NerdBook:dotfiles marc$
```

Start by reproducing the global installation failure with `sudo npm install -g dotfiles`, then inspect the `bin/dotfiles` entry point and the dependency information involved in the reported `http-server` peer dependency error. Done means the package installs globally without EPEERINVALID and the installed command remains usable.

Written by the indexing model from the issue text.