Allow "python -m apistar.cli"

[maerteijn]

[rpkilby]

You can define a __main__.py module to enable invoking the package by name (e.g., python -m apistar).

# apistar/__main__.py
from .cli import cli

if __name__ = '__main__':
    cli()

[maerteijn]

I know, but just adding this two lines means no new file and does the job.