Fixed test user generation and encapsulated it

I added the method=post parameter to the /test-user request because fb now requires that. I also encapsulated the code into the generate_fb_user file so that file can be used programmatically to create test users (in a testing suite for example). I also added a hashbang to app.js because running ./app.js is so much nicer than typing node app.js.

Oh and I made the code js-hint clean because why not I guess.