This is the correct lexer for interactive console sessions, according to
<http://pygments.org/docs/lexers/>. This does require command lines to
be prefixed with `$`, otherwise they are interpreted as the output of a
command. It highlights the command nicely, including environment
variables, strings, and comments.
While the project template is intended to be as generic as possible, and not everyone will want to use requirements.txt (some would prefer to use setup.py to define requirements, for example), we need some way to formally indicate that the project template is specific to Django 1.8.
