Command line utility improvements

1. turnpike create project now outputs the minimal package.json you
   need to get started (finally...)
2. turnpike drive and turnpike testdrive check process.cwd() for an
   installed copy of turnpike, and will use that to start your server.

   This not only ensures some basic sanity, it also fixes a weird 404
   error you've probably been seeing a lot of in local testing.
0.2.1