Script to init node_modules and start server

I don't use `coffee` much, so I don't have the global coffee npm installed.

Typing `./node_modules/coffee-script/bin/coffee app.coffee` is tiresome, so I wrote a little script in the project root to start the app with either a global (if the user has it) or project-local `coffee`.

I threw in a check for *node_modules* and run `npm install` if it's missing. Running `start.sh` immediately after cloning sets up everything.

I added a few lines in the README to that effect.

Side-note: I think I have to deploy this to my company LAN tomorrow because **everyone** in my office is going to want to use it :thumbsup: It's super awesome.