I'm not exactly sure we'll go that route, but it will make deployment
clearer.

Note that this involves renaming the main script, which makes the
directory listing a little more confusing and redundant, but it makes
the `setup.py` stuff easier (because we don't need to rename the
file).

The downside is that it doesn't look like a python module anymore,
which confuses some tools, but we can always add a symlink in the
source (like we do in undertime) to workaround that problem, in the
future.

Closes: #3