Firebase NPM doesn't expose the token generator dependency

README.md

There are some ways to fix this:

1. Remove dependency and let users install it manually as needed, the token generator isn't really a hard dependency of Firebase anyway
2. Expose the dependency from the firebase module:

    var Firebase = require('firebase')
        FirebaseTokenGenerator = Firebase.TokenGenerator

install.sh

$ mkdir firebase-npm-test
$ cd firebase-npm-test
$ npm install firebase
npm http GET https://registry.npmjs.org/firebase
npm http 304 https://registry.npmjs.org/firebase
npm http GET https://registry.npmjs.org/firebase-token-generator
npm http GET https://registry.npmjs.org/faye-websocket
npm http 304 https://registry.npmjs.org/faye-websocket
npm http 304 https://registry.npmjs.org/firebase-token-generator
firebase@0.5.0 node_modules/firebase
├── firebase-token-generator@0.1.2
└── faye-websocket@0.4.4

$ node
> require('firebase-token-generator')
Error: Cannot find module 'firebase-token-generator'
    at Function.Module._resolveFilename (module.js:338:15)
    at Function.Module._load (module.js:280:25)
    at Module.require (module.js:362:17)
    at require (module.js:378:17)
    at repl:1:2
    at REPLServer.self.eval (repl.js:109:21)
    at Interface.<anonymous> (repl.js:248:12)
    at Interface.EventEmitter.emit (events.js:96:17)
    at Interface._onLine (readline.js:200:10)
    at Interface._line (readline.js:518:8)
>