Merge pull request #4 from mozilla/models

Models
Start server routes.
Fix package.json
Can create new users.
Can delete users.
Can get data for a specific user.
Allow updating of metadata for a user.
Add `evidence` model.
Add preliminary evidence routes.
Fix evidence routes to match docs.
Add DELETE routes for evidence
Evidence routes should be done.
Add earner badge routes.
Add authorization header to test requests.
Fix model tests
Add request verification middleware
Fix typo in test; more fixtures.