Builds the distribution files: wheels and source.

def build(force):
    """ Builds the distribution files: wheels and source. """
    dist_path = Path(DIST_PATH)
    if dist_path.exists() and list(dist_path.glob('*')):
        if force or click.confirm('{} is not empty - delete contents?'.format(dist_path)):
            dist_path.rename(DIST_PATH_DELETE)
            shutil.rmtree(Path(DIST_PATH_DELETE))
            dist_path.mkdir()
        else:
            click.echo('Aborting')
            sys.exit(1)

    subprocess.check_call(['python', 'setup.py', 'bdist_wheel'])
    subprocess.check_call(['python', 'setup.py', 'sdist',
                           '--formats=gztar'])