The .gitignore now specifies a 'mines', 'solutions' and 'media' directory
to ignore in the repository root.

README no longer mentions removing autoregister in the future since it
is quite nice for new deployments.

The install script now runs installs from ``requirements.pip`` and runs
migrations for you. This replaces running migrations in the rmdb script.

The results management command now returns prematurely if no mines
or solutions are specified by the given arguments.

The manage.py script shebang now specifies python3.