Add ember.js-app that almost works.

Damn you, authentication.
Get login to work.
Make logout work.
Add component for pin-display.
Rename `description` to `body`.
Run grunt.
Merge branch 'emberjs'

Conflicts:
	server.js
Find user by username.
Send 404 when no user was found under a given username.
Do not nest latitude and longitude in coordinates.
Also send longitude and latitude back.
Sideload pins on hashtag-routes.
Send username instead of ID after login.
Also send username on /login (instead of only /register).
Save avatars on register.