Reactjo

Added
- Reactjo logo.
- Several worklist entries.

Fixed
- Stop printing worklist's when there are no entries to print.

Added
- Worklist entries for content scaffolding.

Changed
- Prevent list pages without details pages.


[Released]

Added
- Content scaffolding is now an option.
- Models, views, serializers, permissions, etc can be scaffolded interactively.
- Models get their own CRUD endpoints in the API.
- Models get frontend list, detail, create, update, and delete components.
- User auth is now an option.
- User auth comes with login, logout, signup, list users, and user/:id details.
- Frontend implements bootstrap and material-ui.

Fix
- Implement the same version automation with `reactjo extend`.

Fix
- Fixed a critical bug caused by the new deploy script.

Changed
- Explicitly declare extension versions.
- Slightly change the usage instructions in README.md.
- Turn "python3" into "python" since the venv should handle that anyway.
- Add a handy deploy script.