Add human representations of models
Tweaks to admin
Move CSS to internal from external

This is because the latter does not work with Little Printer.
Add `OAuth` model
Add `subscription_id` and `credentials` to `LittlePrinter`
Add method to print html on `LittlePrinter`
Add `test_print` method to `LittlePrinter` model
Add `BASE_URL` to Django settings
Add ability to print a user's iterations for a specific day