Feat/clientsideauth

Fixes #78 
Fixes #85 

* Client receives access code then sends to server for server-side user auth through FB
* Server generates JWT after receiving FB access token
* Server then sends JWT back to client
* Client stores JWT in local storage
* If interceptor works as intended in app.js then each subsequent request sent to the server after authentication will have their JWT in the header
* Can test JWT parsing (when client sends subsequent requests when we integrate with SocketIO)