Specify Django port in README

Fixes gh-27.
Move user model tests to test package
Add UserSerializer
Use separate user serializer for logged in user
Add API endpoint for accessing user information
Redirect to logged in user on /users/me/
Add token-based authentication for API

Fixes gh-17.
Fix untestable (?) bug
Use Python 3 style for super
Upgrade ember-cli version
Ignore trailing whitespace in diffs
Add token authentication to Ember
Remove redirect for /user/me/

Fixes error about redirecting after preflight request.
Fix /users/me API test (no redirect)
Fix /users/me for anonymous users
Add a (buggy) welcome message to user
Hide "Welcome," until user name available
Move user name logic into application controller
Use content instead of model on controller
Retrieve user after successful login and display welcome